An efficient and error free operation is the goal of any administrator that is setting up a computer network. Ensuring the smooth running and passing of data without errors or loss of connections is a prerequisite for any decent functioning network system.

There are some fundamental things that can be carried out to minimise risk of encountering problems further down the line. A decent network server is a must, as is an efficient router but there is one piece of technology often overlooked in computer networking – the network time server.

The importance of correct computer network time only becomes apparent when something goes wrong. When an error does occur (and without adequate time synchronization it is a matter of when not if) it can be next to impossible to pin down what caused in and where. Just imagine all the error logs on the different machines all with timestamps telling a different time, finding out where and when the error occurred can be near impossible – and that’s before you can even get round to fixing it.

Fortunately most network administrators appreciate the value of synchronization and most ensure the network receives a time signal from across the Internet. However, many administrators are unaware of the vulnerabilities this may cause throughout the network.

By using an online time server, a UDP port (123) needs be kept open which can be an open gate to malicious programs and users. Furthermore, there is no authentication of the online time server so the signal could be hijacked or just be inaccurate.

A dedicated network time server running the protocol NTP (Network Time Protocol) will operate externally to the network and receive the time from an atomic clock source directly (through radio or GPS) making NTP servers, secure, accurate and reliable.

Richard N Williams is a technical author and specialist in atomic clocks, telecommunications, NTP and network time synchronisation helping to develop dedicated NTP clocks. Please visit us for more information about an NTP server or other NTP time server solutions.

Author: Richard N Williams
Article Source: EzineArticles.com
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Time synchronisation plays an ever more important role in the modern world with more and more technologies reliant on accurate and reliable time.

Time synchronisation is not just important but can also be crucial in the safe running of systems such as air traffic control that simply couldn’t function without accurate synchronisation. Think of the catastrophes that could happen in the air of aircraft were out of synchronisation with each other?

In global commerce too accurate and reliable time synchronisation is highly important. When the world’s stock markets open in the morning and traders from across the world buy stock on their computers. As stock fluctuates second by second if machines are out of synchronisation it could cost millions.

But synchronisation is also imperative in modern computer networking; it keeps systems secure and enables proper control and debugging of systems. Even if a computer network is not involved in any time sensitive transactions a lack of synchronisation can leave it vulnerable to malicious attacks and can also be susceptible to data loss.

Accurate synchronisation is possible in computer networking thanks to two developments: UTC and NTP.

UTC is a timescale -coordinated universal time, it is based on GMT but is controlled by an array of atomic clocks making it accurate to within a few nanoseconds.

NTP is a software protocol – Network Time Protocol, designed to accurately synchronise computer networks to a single time source. Both of these implementations come together in a single device which is relied upon the world over to synchronise computer networks – the NTP server.

An NTP time server or network time server is a device that receives the time from an atomic clock, UTC source and distributes it across a network. Because the time source is continually checked by the time server and is from an atomic clock it makes the network accurate to within a few milliseconds of UTC providing synchronisation on a global scale.

Richard N Williams is a technical author and specialist in atomic clocks, telecommunications, NTP and network time synchronisation helping to develop dedicated NTP clocks. Please visit us for more information about a Galleon ntp server or other ntp server solutions.

Author: Richard N Williams
Article Source: EzineArticles.com
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Network Time Protocol (NTP) is a TCP/IP protocol developed when the internet was in its infancy. It was developed by David Mills of the University of Delaware who was trying to synchronise computers across a network with a degree of precision.

NTP is a UNIX based protocol but it has been ported to operate just as effectively on PCs and a version has been included with operating systems since Windows 2000 (including Windows 7, Vista and XP).

NTP, and the daemon (application) that controls it, is not just a method of passing the time around. Any system running the NTP daemon can act as a client by querying the reference time from other servers or it can make its own time available for other devices to use which in effect turns it into a time server itself. It can also act as a peer by collaborating with other peers to find the most stable and accurate time source to use.

One of the most flexible aspects of NTP is its hierarchical nature. NTP divides devices into strata, each stratum level is defined by its proximity to the reference clock (atomic clock). The atomic clock itself is a stratum 0 device, the closest device to it (often a dedicated NTP time server) is a stratum 1 device whilst other devices that connect to that become stratum 2. NTP can maintain accuracy to within 16 stratum levels.

Any network that needs to be synchronised, has to first identify and locate a time source for NTP to distribute. Internet sources of time are available but thee are often taken from stratum 2 devices that operate through the firewall. The only way NTP can peer the time is if the TCP/IP port is left open to allow the traffic through. This could lead to security issues as malicious users can take advantage of this firewall hole.

Dedicated NTP time servers find a source of time via GPS or radio signals and so don’t leave a network vulnerable to attack. By attaching a NTP time server to a router and entire network of hundreds and even thousands of devices can be synchronised thanks to NTP’s hierarchical structure.

Richard N Williams is a technical author and specialist in atomic clocks, telecommunications, NTP and network time synchronisation helping to develop dedicated NTP clocks. Please visit us for more information about an NTP server or other NTP time server solutions.

Author: Richard N Williams
Article Source: EzineArticles.com
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Keeping computers synchronized on a network is vitally important, especially if the network in question deals with time sensitive transactions. And failing to keep a network synchronized can cause havoc leading to errors, vulnerabilities and endless problems with debugging.

However with the amount of online time servers available from reputable places such as NIST or Microsoft it is often queried as to why computer networks need to be synchronised to an external NTP time server.

These dedicated NTP devices are often seen as an unnecessary expense and many network administrators simply forgo them and connect to an online time server, after-all, it does the same job doesn’t it?

Actually there are two major reasons why NTP servers are not only important but essential for most computer networks and to overlook them could be costly in many ways.

Let me explain. The first reason why an external NTP server is important is accuracy. It’s not that internet time sources are generally inaccurate (although many are) but there is the question of distance the time reference has to travel. Furthermore, in times when the connection is lost -whether it’s because of a local connection fault or the time server itself goes down – the network will start to drift until the connection is restored.

Secondly and perhaps most important is the security issues involved in using an Internet time source. The main problem is that if your connection to a time server through the then a open port (UDP 123 fro NTP requests) has to be left open, And as with any open port that can used as a gateway for malicious software and users.

The reason dedicated NTP time servers are essential for computer networks is that they work completely independently and external to the network’s firewall. Instead of accessing a time source across the Internet they use either GPS or radio transmissions to get the time. And in doing so they can provide accurate time all the time without fear of losing a connection or allowing a nasty Trojan through the firewall.

Richard N Williams is a technical author and specialist in atomic clocks, telecommunications, NTP and network time synchronisation helping to develop dedicated NTP clocks. Please visit us for more information about an NTP server or other NTP time server solutions.

Author: Richard N Williams
Article Source: EzineArticles.com
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Keeping accurate time is essential for many applications and dedicated NTP time servers make the job easy for network administrators. These devices receive an external time signal, often from GPS or sometimes from broadcast signals put out by organisations such as NIST, NPL and PTB (national physics labs from US, UK and Germany).

Synchronization with a NTP time server is made all the more easier thanks to NTP (network time protocol) this software protocol distributes the time source by constantly checking the time on all devices and adjusting any drift to match the time signal that is received.

Time synchronization is not just the concern of large networks. Even single machines and routers ought to be synchronised because at the very least it will help keep a system secure and make error detection a whole lot easier.

Fortunately, most versions of Windows contain a form of NTP. Often it is a simplified version but it is enough to allow a PC to be synchronized with the global time scale UTC (Coordinated Universal Time). On most Windows machines this is relatively easy to do and can be achieved by double clicking on the clock icon in the task bar then selecting a time provider in the internet time tab.

These time sources are internet based meaning that they are external to the firewall so a UDP port has to be left open to allow the time signal to enter. This can cause some security issues so for those wanting perfect synchronization without any security issues then the best solution is to invest in a dedicated time server. These need not be expensive and as they receive an atomic clock time signal externally then here is no breach in the firewall leaving your network secure.

Richard N Williams is a technical author and specialist in atomic clocks, telecommunications, NTP and network time synchronisation helping to develop dedicated NTP clocks. Please visit us for more information about an NTP server or other NTP time server solutions.

Author: Richard N Williams
Article Source: EzineArticles.com
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We are all looking for freebies, particularly in the present financial climate and the internet is not short of them. Free software, free films, free music, almost everything these days has a free version. Even critical applications for our computers and networks such as anti-virus can come free. So it is understandable that when network administrators want to synchronize the time on computer networks they turn to free sources of UTC time (UTC – Coordinated Universal Time) to synchronize their networks using the operating systems’ own inbuilt NTP server.

However, just as there is no such thing as a free lunch, free time sources come with a cost too. To start with all time servers on the internet that are available for the public to use are stratum 2 servers. This means they are devices that receive the time from another device (a stratum 1 time server) that gets it from an atomic clock. While this second hand time source shouldn’t lose too much time compared to the original, for high levels of accuracy there will be a noticeable drift.

Furthermore, internet time sources are based outside the network firewall. For access to the time server a UDP port needs to be left open. This will mean the network firewall will intrinsically have a hole in it which could be manipulated y a malicious user or aggressive malware.

Another consideration is the inbuilt security that the time transfer protocol NTP (Network Time Protocol) uses to assess the time signal it receives is genuine. This is referred to as authentication but is unavailable across the internet. Meaning the time source may not be what it claims to be and with a hole in the firewall it could result in a malicious attack.

Internet time sources can also be unreliable. Many are too far from clients to provide any real accuracy some time sources available on the internet are wildly out (some by hours not just minutes). There are however, more reputable stratum 2 servers available and the NTP pool has details of those.

For real accuracy with none of the security threats the best solution is to use an external time source. The best method for doing this is to utilise a dedicated NTP server. These devices work exterior to the firewall and receive the time either direct from GPS satellites or via broadcasts by national physics labs such as NIST or NPL.

Richard N Williams is a technical author and specialist in atomic clocks, telecommunications, NTP and network time synchronisation helping to develop dedicated NTP clocks. Please visit us for more information about an NTP server or other NTP time server solutions.

Author: Richard N Williams
Article Source: EzineArticles.com
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Most businesses these days rely on a computer network. Computers in most organisations conduct thousands of tasks a second, from controlling production lines; ordering stock; preparing financial records and communicating with computers on other networks – often from the other side of the world.

Computers use just one thing to keep track of all these tasks: time. Timestamps are the computers only reference for when an event or task occurs in relation to other events. They receive time in the form of timestamps and they measure time in periods of milliseconds (thousandth of a second) as they may conduct hundreds of processes each second.

A global timescale known as UTC (Coordinated Universal Time) has been developed to ensure computers from different organisations all over the world can synchronise together. So what happens if the clocks on computers don’t coincide with each other or with UTC?

The consequences of running a network with computers that are not synchronised can be disastrous. Here are five reasons why all businesses need adequate network synchronisation using a NTP server (Network Time Protocol) or other network time server device.

1. Tasks fail to happen:

When computers are running at different times, events on different machines can fail to happen as often a PC may assume an event on another machines has already happened if the time for that event has passed according to its own clock. And what is worse, when one task fails it has a knock-on effect with other tasks failing to happen and in turn causing further tasks to fail.

2. Loss of Data:

When tasks fail to happen it soon gets noticed but when networks are not synchronised data that is meant to be kept can quite easily be lost and it can go unnoticed for quite a while. Data can be lost because storage as and retrieval is also reliant on time stamps.

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.

Richard N Williams and Richard Hawkesford are technical authors and specialists in atomic clocks, telecommunications, NTP and network time synchronisation helping to develop dedicated NTP clocks. Please visit us for more information about an NTP server or other network time server solutions.

Author: Richard N Williams
Article Source: EzineArticles.com
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Windows 7, the latest operating system from Microsoft is also their first operating system that automatically synchronizes the PC clock to an internet source of UTC time (Coordinated Universal Time). From the moment a Windows 7 computer is switched on and is connected to the Internet it will request time signals from the Microsoft time service – time.windows.com.

While for many home users this will save them the hassle of setting and correcting their clock as it drifts, for business users it may be problematic as internet time sources are not secure and receiving a time source through the UDP port on the firewall could lead to security breaches and as Internet time sources can’t be authenticated by NTP (Network Time Protocol) the signals can be hijacked by malicious users.

This internet time source can be deactivated by opening the clock and date dialogue box, and opening the Internet Time tab, clicking the ‘Change’ setting button and unchecking the ‘Synchronize with an Internet time server option.’

Whilst this will unsure no unwanted traffic will be coming through your firewall it will also mean that the Windows 7 machine will not be synchronized to UTC and its timekeeping will be reliant on the motherboard clock, which will eventually drift.

To synchronize a network of Windows 7 machines to an accurate and secure source of UTC then the most practical and simplest solution is to plug in a dedicated NTP time server. These connect directly to a router or switch and enable the safe receiving of an atomic clock time source.

NTP time servers use the highly accurate and secure GPS signal (Global Positioning System) available everywhere on the planet or more localized long wave radio signals transmitted by several national physics laboratories such as NIST and NPL.

Richard N Williams is a technical author and specialist in atomic clocks, telecommunications, NTP and network time synchronisation helping to develop dedicated NTP clocks. Please visit us for more information about an NTP server or other NTP time server solutions.

Author: Richard N Williams
Article Source: EzineArticles.com
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Time servers, often referred to as NTP time servers after the protocol (Network Time Protocol) used to distribute time are an increasingly important part of any computer network. The NTP server receives a timing signal from an accurate source (such as an atomic clock) and then distributes it to all devices on the network.

However, despite the increasing importance of these time synchronisation devices, many network administrators still fail to accurately synchronise their networks and can leave their entire computer system vulnerable.

Here are seven reasons why a NTP time server is a crucial piece of equipment for YOUR network:

o Security: NTP servers use an external source of time and don’t rely on an open firewall port. An unsynchronized server will also be vulnerable to malicious users who can take advantage of time differences.

o Error logging: failing to adequately synchronize a computer network may mean that it is near impossible to trace errors or malicious attack, especially if the times on the log files from different machine do not match.

o Legal Protection: Not being able to prove the time can have legal implications if somebody has committed fraud or other illegal activity against your company.

o Accuracy: NTP Time Servers ensure that all networked computers are synchronized automatically to the exact time throughout your network so everybody in your company can have access to the exact time.

o Global Harmony: A global timescale known as UTC (Coordinated Universal Time) has been developed to ensure that systems across the globe can run the exact same time. By utilising a NTP server not only will every device on you network be synchronised together but your network will be synchronised with every other network on Earth that is hooked up to UTC.

o Control: With a NTP server you have control of the configuration. You can allow automatic changes each spring and autumn for daylight saving time or set your server time to be locked to UTC time only – or indeed, any time zone you choose.

o Automatic update of time. No user intervention required, a NTP time server will account for leap seconds and time zones ensuring trouble free synchronisation.

Richard N Williams is a technical author and specialist in atomic clocks, telecommunications, NTP and network time synchronisation helping to develop dedicated NTP clocks. Please visit us for more information about an NTP server or other NTP time server solution.

Author: Richard N Williams
Article Source: EzineArticles.com
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1. The business world is now more global than ever with as much likelihood of your customer’s being from the other side of the planet as from around the corner. Any transactions conducted virtually across the Internet require adequate time synchronisation otherwise your company can be open to abuse or fraud, customers may claim they paid you at a certain time but how do you ascertain if they have without adequate synchronisation?

2. Does your system conduct time sensitive transactions? Computers have only one reference between events and that is time. If a network is not synchronised then many events and transactions may fail to happen. This can have a knock-on effect as one transaction or event fails so do others and without adequate synchronisation it may be quite a while before anyone realises the errors.

3. Do you have valuable or sensitive data? A lack of synchronisation can often lead to data loss. Storage and retrieval is also time reliant so if a computer believes the time data should have been saved has past then it may assume the data is already saved. The problem can be exaggerated if the data is continually updated as the inaccurate timestamps may mean that certain updates are not completed.

4. Is security important to your business? A lack of time synchronisation can leave a computer network open to malicious users, hackers and even fraud. If computers on a network are running different times then this can be exploited by malicious users and without time synchronisation you may not even know they have been there. A perfectly synchronised network will also offer legal protection with a NTP server (Network Time Protocol) being auditable and unquestioned in a court of law.

5. Is the credibility of your company important? A lack of synchronisation can be extremely costly not just in time and money but also in the credibility of your company. Without synchronisation a network will be vulnerable to mistakes and while these may be easily rectified once a customer has to complain word will soon get out.

Running a synchronised network adhering to Universal Coordinated Time (UTC) the world’s standard timescale is fairly simple. Dedicated NTP time servers that receive a UTC time source from either a radio transmission or the GPS network (Global Positioning System) are readily available, simple to set up, accurate and secure.

Richard N Williams is a technical author and specialist in atomic clocks, telecommunications, NTP and network time synchronisation helping to develop dedicated NTP clocks. Please visit us for more information about an NTP server or other network time server solutions.

Author: Richard N Williams
Article Source: EzineArticles.com
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Even when the Internet when was its infancy, with no more than a few computers connected together it became apparent that there was a need for time synchronisation. Computers are easily confused particularly with time which can only travel in one direction.

When a communication is sent from one computer and received by seems to have arrived before it was sent and this can cause unforeseen problems.

Think about buying an airline ticket only to turn up at the airport to find somebody has bought your seat after you did because they booked it on a computer with a slower clock!

Dr David Mills of the University of Delaware, realised the need for a synchronisation tool and developed Network Time Protocol (NTP). Although not the first and only time synchronisation protocol it is by far the most widely used and probably owes its success, to the now Professor Mills, and his dedicated team for its continual development.

What started out as a protocol that could manage synchronisation to a few milliseconds is now able to keep computer clocks to within a few nanoseconds of each other (milli = 1/thousandth nano= 1/billionth).

NTP is hierarchical and is divided into Strata. A clock source is referred to as stratum 0, whilst a NTP time server is stratum 1, Computers and devices that receive a time from a stratum 1 server become stratum 2 and so on.

This hierarchical structure means that tens of thousands of devices can synchronise to the same time whilst not inundating the NTP time server or the bandwidth of the network.

NTP time servers rely on using a reference clock. whilst this can be anything from a wrist watch or a computer’s system clock, it would be pointless to use a reference clock that was not accurate in itself.

Most networks that use a NTP time server will use a UTC time source. UTC or Coordinated Universal Time is based on the time told by the incredibly accurate and expensive atomic clocks. An atomic clock’s time signals can be picked up either from across the Internet (although accuracy varies and is dependent on distance), specialist radio transmissions broadcast in several countries (including the US, UK, Germany, France and Japan) or via the American GPS (Global Positioning System).

The NTP time servers then distribute this stratum 0 time source between all devices on a network that connects with the NTP time server. NTP will either then advance or hold the system clock to match with the timing reference.

NTP also has in-built security measures called authentication. these are a set of keys that are encrypted and used to identify both client and server. Unfortunately authentication is unavailable on Internet time references which is why both Microsoft and Novell suggest hardware sources should be used as a timing reference.

NTP is currently on version 4 with version 5 under development and is open source and freely available to download via ntp.org.

Richard N Williams is a technical author and specialist in atomic clocks, telecommunications, NTP and network time synchronisation helping to develop dedicated NTP clocks. Please visit us for more information about a network time server or other ntp server solutions.

Author: Richard N Williams
Article Source: EzineArticles.com
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Network Time Protocol (NTP) is an Internet standard protocol designed over 25 years ago and still under constant development. NTP synchronises devises on a network to a single timing source. If time on a network is not synchronised when applications are conducted over the Internet unintended results can occur such as email being received before it was sent or time sensitive applications failing.

NTP uses a single reference clock to synchronise all clocks on a network to that time. UTC time (Coordinated Universal Time) is the world’s official time standard and most NTP servers are synchronized to receive UTC time. UTC time is kept accurate by a constellation of atomic clocks which ensure that all UTC timing references tell the same time.

NTP is organized into a hierarchy. At the top of the hierarchy are the atomic reference clocks, these are known as stratum 0. Below this strata are servers that receive a timing reference directly from a stratum 0 source. Stratum 2 servers receive time from a stratum 1 server and so on.

NTP is highly scalable meaning a synchronisation network may consist of several reference clocks and NTP will select the best candidates to build its estimate of the current time. This makes NTP highly accurate, with precision of a few hundred nano-seconds not unheard of (nano = 1 second every billion years!)

To synchronise a computer clock to timing reference using NTP extremely simple to do with modern operating systems. Most operating system manufacturers install a version of NTP into their systems (albeit a scaled down version, known as SNTP in some).

This means to connect to an Internet stratum 1 time server a user merely has to insert the domain address in the NTP program. This can be done quite simply in windows by double clicking the system clock and opening up the Internet Time tab. On UNIX the ntp.conf file contains the DNS details.

It should be mentioned that Microsoft, amongst others, recommend using an external hardware source as a timing reference as Internet sources cannot be authenticated leaving a network open to malicious attacks.

An external NTP server can receive a UTC timing signal either through a specialist national radio broadcast (so long as the receiver is within range of a suitable transmission) or from the GPS network (via a GPS antenna).

NTP servers are relatively low cost and easy to install and setup, providing accuracy and precision whilst also offering security.

Richard N Williams is a technical author and a specialist in the telecommunications and network time synchronisation industry helping to develop dedicated NTP clocks. Please visit us for more information about NTP or other network time server solutions.

Author: Richard N Williams
Article Source: EzineArticles.com
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NTP servers or Network Time Protocol are devices that connect to a computer network and synchronise all machines to a single time source. Of course most Windows operating systems have an inbuilt NTP program called Windows Time that can synchronise to an Internet time source; however, these can not be authenticated and can leave a computer network open to abuse.

NTP servers are normally rack mountable and take up 1U of space but some are built smaller for networks without a dedicated server room. NTP is based on UDP and requires TCP/IP.

The timing source for an NTP server can either be taken from a specialist radio transmission that are broadcast from national physics laboratories or from the GPS network.

Radio time references are only broadcast by a few countries, in particular the US (WWVB), the UK (MSF), Germany (DCF), Japan (JJY), France (TDF), Switzerland (HBG) and China (BPM). However, depending on the distance from these transmissions it is possible to receive the signals in neighbouring countries although being mainly long wave these signals are easily blocked by mountains, buildings and bad weather.

If a NTP Server is in a location with a clear radio signal it is possible to receive the transmission indoors which has an advantage over the GPS system which requires and antenna with a clear view of the sky (although it is possible to receive a transmission near a window).

GPS is however more accurate than radio transmission and can provide accuracy to within a hundred nanoseconds (a nanosecond is 1 billionth of a second). They can also receive a signal from literally anywhere in the world (as long as the antenna can get a clear view of the sky).

NTP servers are extremely easy to install and just need to be provided with a static IP address and have its internal time synchronized with the external timing reference. Once synchronised (which can take up to an hour) the NTP server will continually ensure all the clocks on the network are running the correct time.

Heightened security options such as authentication can also be used to ensure the NTP Server and network is secure from abuse.

Richard N Williams is a technical author and a specialist in the telecommunications and network time synchronisation industry helping to develop dedicated NTP clocks. Please visit us for more information about NTP or other network time server solutions.

Author: Richard N Williams
Article Source: EzineArticles.com
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Sourcing the correct time for network synchronisation is only possible thanks to atomic clocks. Compared to standard timing devices and atomic clock is millions of times more accurate with the latest designs providing accurate time to within a second in a 100,000 years.

Atomic clocks use the unchanging resonance of atoms during different energy states to measure time providing an atomic tick that occurs nearly 9 billion times a second in the case of the caesium atom. In fact the resonance of caesium is now the official definition of a second having been adopted by the International System of Unit (SI).

These clocks are the base used for the international time, UTC (Coordinated Universal Time). And they also provide the basis for NTP servers to synchronise computer networks and time sensitive technologies such as those used by air traffic control and other high level time sensitive applications.

Finding an atomic clock source of UTC is a simple procedure. Particularly with the presence of online time sources such as those provided by Microsoft and the National Institute for Standards and Time (windows.time.com and nist.time.gov).

However, these NTP servers are what are known as stratum 2 devices that mean they are connected to another device which in turn gets the time from an atomic clock (in other words a second-hand source of UTC).

While the accuracy of these stratum 2 servers is unquestionable, it can be affected by the distance the client is from the time servers, they are also outside the firewall meaning that any communication with an online time server requires an open UDP (User Datagram Protocol) port to allow the communication.

This can cause vulnerabilities in the network and are not used for this reason in any system that requires complete security. A more secure (and reliable) method of receiving UTC is to use a dedicated NTP time server. These time synchronisation devices receive the time direct from atomic clocks either broadcast on long wave by places like NIST or NPL (National Physical Laboratory – UK). Alternatively UTC can be derived from the GPS signal broadcast by the constellation of satellites in the GPS network (Global Positioning System).

Richard N Williams is a technical author and specialist in atomic clocks, telecommunications, NTP and network time synchronisation helping to develop dedicated NTP clocks. Please visit us for more information about an NTP server or other NTP time server solutions.

Author: Richard N Williams
Article Source: EzineArticles.com
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Time synchronisation is often a much underrated aspect of computer management. Generally time synchronisation is only crucial for networks or for computers that a take in time sensitive transactions across the internet.

Time synchronisation with modern operating systems such as Windows Vista, XP or the different versions of Linux is relatively easy as most contain the time synchronisation protocol NTP (Network Time Protocol) or a simplified version at least (SNTP).

NTP is an algorithm based program and works by using a single time source that can be distributed amongst the network (or a single computer) and is constantly checked to ensure the network’s clocks is running accurately.

For single computer users, or networks where security and precision are not primary concerns (although for any network security should be a main issue) then the simplest method of synchronising a computer is to use an internet time standard.

With a Windows operating system this can easily be done on a single computer by double clicking the clock icon and then configuring the internet time tab. However, it must be noted that in using an internet based time source such as nist.gov or Microsoft, a port will have to be left open in the firewall which could be taken advantage of by malicious users.

For network users and those not wanting to leave vulnerabilities in their firewall then the most suitable solution is to use a dedicated network time server. Most of these devices also use the protocol NTP but as they receive a time reference externally to the network (usually by way of GPS or long wave radio) the leave no vulnerabilities in the firewall.

These devices are also far more reliable and accurate than internet time sources as they communicate directly with the signal from an atomic clock rather than being several tiers (in NTP terms known as strata) from the reference clock as most internet time sources are.

Richard N Williams is a technical author and specialist in atomic clocks, telecommunications, NTP and network time synchronisation helping to develop dedicated NTP clocks. Please visit us for more information about an NTP server or other NTP time server solution.

Author: Richard N Williams
Article Source: EzineArticles.com
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