Category: GPS

The Hidden Cost of Free Time

  |   By

If you are reading this then you are probably aware of the importance time plays in IT systems and computer networks. Most computer administrators appreciate that precise time and accurate synchronisation are an important aspect of keeping a computer network error free and secure.

And yet, despite its importance many network administrators still rely on the Internet as a source of UTC time for their networks (UTC – Coordinated Universal Time), primarily because they see it as a quick and more importantly a free method of time synchronisation.

However, the drawbacks in using these free services may cost a lot more than the money saved on a dedicated NTP time server.

NTP (Network Time Protocol) is now present on nearly all computers and it is NTP that is used to synchronise computer systems. However, if an Internet time source is used then the source is outside the network firewall and this creates a serious vulnerability. Any external time source will require a port to be left open in the firewall to allow the time information packets through and this opening is too easy a way to exploit a network which can become victim to a DDOS attack (Distributed Denial of Service) or even allow malicious programmes through to take control of the machines themselves.

Another problem is the availability of stratum 1 time sources across the internet. Most online time sources come from stratum 2 time servers. These are devices that receive the time from a time server (stratum 1) that originally gets the information from an atomic clock (stratum 0).  While stratum 2 devices can be just as accurate as stratum 1 time servers, across the internet without NTP authentication the actual accuracy can not be guaranteed.

Furthermore, internet time sources have never been considered accurate or precise with surveys showing over half being inaccurate by over a second and the rest dependent on the distance from client as to whether they can provide any useful accuracy. Even organisations such as NIST publish  advisory notices on their time server pages about it unable to guarantee security or accuracy and yet millions of networks are still receiving time from across the internet.

With the decline in cost of dedicated radio referenced NTP time servers or GPS NTP server there has never been a better time to get one. And when you consider the cost of a computer breach or crashed network the NTP server will have paid for itself many times over.

Does your Business Need a NTP time server? Five Questions to Ask Yourself

  |   By

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.

Time Server Synchronisation The basics

  |   By

NTP (Network Time Protocol) is an internet based protocol designed to synchronise the clocks on a computer network. It is the main time synchronisation software used in computer networks and is also packaged with most operating systems.

An NTP server is a dedicated device that receives a single time source then distributes it amongst all devices on a network. The protocol NTP monitors the drift of the internal clocks on a network and corrects for them.

An NTP server can receive a time source from either a national physical laboratory such as the UK’s National Physical Laboratory (NPL), however, these time signals are broadcast via long wave radio and have finite range.

GPS NTP servers are designed to receive the time source generated by the atomic clocks onboard GPS satellites (Global Positioning System). GPS is available anywhere on the planet as a time source as long as there is a clear view of the sky.

Without correct synchronisation all sorts of potential problems can occur such as leaving a computer system vulnerable to fraud, malicious users and hackers. An unsynchronised computer network may also lose data and be difficult to audit.

A global timescale called UTC (Coordinated Universal Time) has been developed to ensure the entire world uses the same timescale. The NTP server utilise UTC ensuring the computer network is telling the same time as every other computer network.

NTP Server running a network (Part 1)

  |   By

NTP servers are a vital tool for any business that needs to communicate globally and securely. NTP servers distribute Coordinated Universal Time (UTC), the world’s global timescale based on the highly accurate time told by atomic clocks.

NTP (Network Time Protocol) is the protocol used to distribute the UTC time across a network it also ensures all time is accurate and stable. However, there are many pitfalls in setting up a NTP network, here are the most common:

Using the correct time source

Attaining the most suitable time source is fundamental in setting up a NTP network. The time source is going to be distributed amongst all machines and devices on a network so it is vital that it is not only accurate but also stable and secure.

Many system administrators cut corners with a time source. Some will decide to use an Internet based time source although these are not secure as the firewall will require an opening and also many internet sources are either wholly inaccurate or too far away to afford any useful precision.

There are two highly secure methods of receiving a UTC time source. The first is to utilise the GPS network which although doesn’t transmit UTC, GPS time is based on International atomic time and is therefore easy for NTP to convert. GPS time signals are also readily available all over the globe.

The second method is to use the long wave radio signals broadcast by some national physical laboratories. These signals, however, are not available in every country and they have a finite range and are susceptible to interference and local topography.

Keeping Track of the Worlds Time and Difficulties in Synchronisation

  |   By

Until 1967 the second was defined using the motion of the Earth which rotates once on its axis every 24 hours, and there are 3,600 seconds in that hour and 86,400 in 24.

That would be fine if the earth was punctual but in fact it is not. The Earth’s rotation rate changes every day by thousands of nanoseconds, and this is due in a large part to wind and waves spinning around the Earth and causing drag.

Over the course of thousands of days, these changes in the rate of rotation can result in the Earth’s spin getting out of synch with the high-precision atomic clocks that we use to keep the UTC system (Coordinated Universal Time) ticking over. For this reason the Earth’s rotation is monitored and timed using the far off flashes from a type of collapsed star called a quasar that flash with an ultra precise rhythm many millions of light years away. By monitoring the Earth’s spin against these far away objects it can be worked out how much the rotation has slowed.

Once a second of slowing has been built up, The International Earth Rotation Service (IERS), recommends a Leap Second to be added, usually at the end of the year.

Other complications arise when it comes to synchronising the Earth to one timescale. In 1905, Albert Einstein’s theory of relativity showed that there is no such thing as absolute time. Every clock, everywhere in the universe, ticks at a different rate. For GPS, this is an enormous issue because it turns out that the clocks on the satellites drift by almost 40,000 nanoseconds per day relative to the clocks on the ground because they are high above the Earth’s surface (and therefore in a weaker gravitational field) and are moving fast relative to the ground.

And as light can travel Forty-thousand feet in that time, you can see the problem. Einstein’s equations first written down in 1905 and 1915 are used to correct for this time-shift, allowing GPS to work, planes to navigate safely and GPS NTP servers to receive the correct time.

Correcting Network Time

  |   By

Distributed networks rely completely on the correct time. Computers need timestamps to order events and when a collection of machines are working together it is imperative they run the same time.

Unfortunately modern PC’s are not designed to be perfect timekeepers. Their system clocks are simple electronic oscillators and are prone to drift. This is not normally a problem when the machines are working independently but when they are communicating across a network all sorts of problems can occur.

From emails arriving before they have been sent to entire system crashes, lack of synchronisation can causes untold problems across a network and it is for this reason that network time servers are used to ensure the entire network is synchronised together.

Network time servers come in two forms – The GPS time server and the radio referenced time server. GPS NTP servers use the time signal broadcast from GPS satellites. This is extremely accurate as it is generated by an atomic clock on board the GPS satellite. Radio referenced NTP servers use a long wave transmission broadcast by several national physics laboratories.

Both these methods are a good source of Coordinated Universal Time (UTC) the world’s global timescale. UTC is used by networks across the globe and synchronising to it allows computer networks to communicate confidently and partake of time sensitive transactions without error.

Some administrators use the Internet to receive a UTC time source. Whilst a dedicated network time server is not required to do this it does have security drawbacks in that a port is needed to be left open in the firewall for the computer to communicate with the NTP server, this can leave a system vulnerable and open to attack. Furthermore, Internet time sources are notoriously unreliable with many either too inaccurate or too far away to serve any useful purpose.

Why the Need for NTP

  |   By

Network Time Protocol is an Internet protocol used to synchronize computer clocks to a stable and precise time reference. NTP was originally developed by Professor David L. Mills at the University of Delaware in 1985 and is an Internet standard protocol.

NTP was developed to solve the problem of multiple computers working together and having the different time. Whilst, time usually just advances, if programs are running on different computers time should advance even if you switch from one computer to another. However, if one system is ahead of the other, switching between these systems would cause time to jump forward and back.

As a consequence, networks may run their own time, but as soon as you connect to the Internet, effects become visible. Just Email messages arrive before they were sent, and are even replied to before they were mailed!

Whilst this sort of problem may seem innocuous when it comes to receiving email, however, in some environments a lack of synchronisation can have disastrous results this is why air traffic control was one of the first applications for NTP.

NTP uses a single time source and distributes it amongst all devices on a network it does this by using an algorithm that works out how much to adjust a system clock to ensure synchronisation.

NTP works on a hierarchical basis to ensure there are no network traffic and bandwidth problems. It uses a single time source, normally UTC (coordinated universal time) and receives time requests from the machines on the top of the hierarch which then pass the time on further down the chain.

Most networks that utilise NTP will use a dedicated network time server to receive their UTC time signal. These can receive the time from the GPS network or radio transmissions broadcast by national physics laboratories. These dedicated NTP time servers are ideal as they receive time direct from an atomic clock source they are also secure as they are situated externally and therefore do not require interruptions in the network firewall.

New Waterproof GPS Mushroom Antenna

  |   By

Galleon Systems’ new mushroom GPS antenna provide increased reliability in receiving GPS timing signals for NTP time servers.
The new Exactime 300 GPS Timing and Synchronization Receiver boasts waterproof protection, anti-UV, anti-acidity and anti-alkalinity properties to ensure reliable and continual communication with the GPS network.

The attractive white mushroom is smaller than conventional GPS antennas and sits just 77.5mm or 3.05-inch in height and is easily fitted and installed thanks to the inclusion of a full installation guide and CD manual.

Whilst an ideal unit for a GPS NTP time server this industry standard antenna is also ideal for all GPS receiving needs including: Marine Navigation, Control Vehicle Tracking and NTP synchronisation
The main features of the Exactime 300 mushroom antenna are:

• Built-in patch antenna • 12 parallel tracking channels • Fast TTFF (Time to first fix) and low power consumption • On-board, rechargeable battery sustained Real-Time Clock and control • parameters memory for fast satellite acquisition during power-up • Interference filter to major VHF channels of marine radar • WAAS compliant with EGNOS support • Perfect Static Drift for both of speed and course •  Magnetic Declination compensation • Is protected against reverse polarity voltage • Support RS-232 or RS-422 interface, Support 1 PPS output.

Utilising UTC

  |   By

To receive and distribute and authenticated UTC time source there are currently two types of NTP server, the GPS NTP server and the radio referenced NTP server. While both these systems distribute UTC in identical ways the way they receive the timing information differs.

A GPS NTP time server is an ideal time and frequency source because it can provide highly accurate time anywhere in the world using relatively cheap components.  Each GPS satellite transmits in two frequencies L2 for the military use and L1 for use by civilians transmitted at 1575 MHz, Low-cost GPS antennas and receivers are now widely available.

The radio signal transmitted by the satellite can pass through windows but can be blocked by buildings so the ideal location for a GPS antenna is on a rooftop with a good view of the sky. The more satellites it can receive from the better the signal. However, roof-mounted antennas can be prone to lighting strikes or other voltage surges so a suppressor is highly recommend being installed inline on the GPS cable.

The cable between the GPS antenna and receiver is also critical. The maximum distance that a cable can run is normally only 20-30 metres but a high quality coax cable combined with a GPS amplifier placed in-line to boost the gain of the antenna can allow in excess of 100 metre cable runs. This can provide difficulties in installation in larger buildings if the server is too far from the antenna.

An alternative solution is to use a radio referenced NTP time server. These rely on a number of national time and frequency radio transmissions that that broadcast UTC time. In Britain the signal (called MSF) is broadcast by the National Physics Laboratory in Cumbria which serves as the United Kingdom’s national time reference, there are also similar systems in the USA (WWVB) and in France, Germany and Japan.

A radio based NTP server usually consists of a rack-mountable time server, and an antenna, consisting of a ferrite bar inside a plastic enclosure, which receives the radio time and frequency broadcast. It should always be mounted horizontally at a right angle toward the transmission for optimum signal strength. Data is sent in pulses, 60 a second. These signals provides UTC time to an accuracy of 100 microseconds, however, the radio signal has a finite range and is vulnerable to interference.

Keeping Time with the Rest of the World

  |   By

A time server is a common office tool but what is it for?

We are all used to having a different time from the rest of the world. When America is waking up, Honk Kong is going to bed which is why the world is divided into time zones. Even in the same time-zone there can still be differences. In mainland Europe for instance most countries are an hour ahead of the UK because of Britain’s seasonal clock changing.

However, when it comes to global communication, having different times all over the world can cause problem particularly if you have to conduct time sensitive transactions such as buying or selling shares.

For this purpose it was clear by the early 1970’s that a global timescale was required. It was introduced on 1 January 1972 and was called UTC – Coordinated Universal Time. UTC is kept by atomic clock but is based on Greenwich Meantime (GMT – often called UT1) which is itself a timescale based on the rotation of the Earth. Unfortunately the Earth varies in its spin so UTC accounts for this by adding a second once or twice a year (Leap Second).

Whilst controversial to many, leap seconds are needed by astronomers and other institutions to prevent the day from drifting otherwise it would be impossible to work out the position of the stars in the night sky.

UTC is now used all over the world. Not only is it the official global timescale but is used by hundreds of thousands of computer networks all over the world.

Computer networks use a network time server to synchronise all devices on a network to UTC. Most time servers use the protocol NTP (Network Time Protocol) to distribute time.

NTP time servers receive the time from atomic clocks by either long-wave radio transmissions from national physics laboratories or from the GPS network (Global Positioning System). GPS satellites all carry an onboard atomic clock that beams the time back to Earth. Whilst this time signal is not strictly speaking UTC (it is known as GPS time) because of the accuracy of the transmission it is easily converted to UTC by a GPS NTP server.