Maintaining accurate and synchronised time has never been so important for businesses and organisations. In today’s world, where so many transactions take place online, having a synchronised and accurate network time is crucial for businesses, especially those organisations that conduct their business over the internet or with other computer networks.
A GPS time server is ideal for preventing costly leap seconds that interrupt businesses that operate on a global timescale.
NTP GPS time servers are becoming an essential tool for business networks. With the ability to synchronise hundreds of computer, switches and routers, an NTP GPS time server can keep a network accurate to within a few milliseconds of UTC (Coordinated Universal Time).
UTC is an atomic clock time reference used to ensure all PCs and computer networks, no matter where they are in the world, are all running the same time. NTP time servers are used to receive a times source and distribute it around a network but there are various choices for locating a source of UTC for time reference for synchronisation.
Ethernet NTP digital wall clocks plug into an NTP times server using an Ethernet cable. This means that the time signal is sent from the NTP time server directly to the Ethernet NTP digital wall clock, maintaining its accuracy. The Ethernet digital wall clock never needs setting as it is automatically set by the time signal sent from the times server, which means it will always be accurate, and the Ethernet NTP digital wall clock requires no mains power or batteries as it gets its power form the Ethernet.
To keep precise time, computer networks have to find a source of accurate, precise and secure time, which enables all devices to be synchronised together. One of the most common used devices for achieving this are radio time synchronisation receivers.
Accurate time is one of the most important aspects to keeping a computer network secure and safe. Places such as stock exchanges, banks and air traffic control rely on secure and accurate time. As computers rely on time as their only reference for when events happen, a slight error in a time code could lead to all sorts of errors, from millions being wiped off share prices to aeroplane flight paths being incorrect.
And time doesn’t just need to be accurate for these organizations, but secure too. A malicious user who interferes with a timestamp could cause all sorts of trouble, so ensuring time sources are both secure and accurate is vital.
Security is increasingly important for all sorts of organisations. With so much trade and communication conducted over the internet, using a source of accurate and secure time is as important a part of network security as anti-virus and firewall protection.
Despite the need for accuracy and security, many computer networks still rely on online time servers. Internet sources of time are not only unreliable, with inaccuracies commonplace, and distance and latency affecting the precision, but an Internet time server is also unsecure and able to be hijacked by malicious users.
But an accurate, reliable and completely secure source of time is available everywhere, 365 days a year—GPS.
While commonly thought of as a means of navigation, GPS actually provides an atomic clock time code, direct from the satellite signals. It is this time code that navigation systems use for calculating position but it is just as effective to provide a secure time stamp for a computer network.
Organizations that rely on accurate time for safety and security all use GPS, as it is a continuous signal, that never goes down, is always accurate and can’t be interfered with by third parties.
To utilise GPS as a source of time, all that is required is a GPS time server. Using an antenna, the time server receives the GPS signal, while NTP (Network Time Protocol) distributes it around the network.
With a GPS time server, a computer network is able to maintain accuracy to within a few milliseconds of the atomic clock time signal, which is translated into UTC time (Coordinated Universal Time) thanks to NTP, ensuring the network is running the same accurate time as other networks also synchronised to a UTC time source.
In a global economy time has become a more crucial than ever before. As people across the globe, communicate, conference and buy and sell from each other, being aware of the each other’s time is vital for conducting business successfully.
And with the internet, global communication and time awareness are even more important as computers require a source of time for nearly all their applications and processes. The difficulty with computer communication, however, is that if different machines are running different times, all sorts of errors can occur. Data can get lost, errors fail to log; the system can become unsecure, unstable and unreliable.
Time synchronisation for computer networks communicating with each other is, therefore, essential – but how is it achieved when different networks are in different time-zones?
The answer lies with Universal Coordinated Time (UTC) an international time-zones developed in the 1970’2 that is based on accurate atomic clocks. UTC is set the same the world over, with no accounting for time-zones so the time on a network in the UK – will be identical to the network time in the USA.
UTC time on a computer network is also kept synchronised through the use of NTP (Network Time Protocol) and an NTP server. NTP ensures all devices on a networked system have exactly the right time as different computer clocks will drift at varying rates – even if the machines are identical.
While UTC makes no accounting for time-zones system clocks can still be set to the local time-zone but the applications and functions of a computer will use UTC.
UTC time is delivered to computer networks through a variety of sources: radio signals, the GPS signal, or across the internet (although the accuracy of internet time is debatable). Most computer networks have a NTP time server somewhere in their server room which will receive the time signal and distribute it through the network ensuring all machines are within a few milliseconds of UTC and that the time on your network corresponds to every other UTC network on the globe.
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.
Keeping the clock on a PC system synchronised is important for many systems, networks and users that need time accuracy for applications and transactions. Nearly everything on a modern computer system is time reliant so when synchronisation fails all sorts of issues can arise from data getting lost and debugging becoming near impossible.
There are several methods of synchronising a computer system’s clock but the majority of them rely on the time synchronisation protocol NTP (Network Time Protocol).
By far the most common method is to make use of the myriad of online NTP time servers that relay the UTC time (Coordinated Universal Time). However, there are many common issues in using internet based time servers – here are some of them:
Can’t access the Internet time server
A common occurrence with Internet time sources is the inability to access them. This can be caused by several reasons:
• Too much traffic trying to access the server
• Website is down
• Your connection is down
The time from the time server is innacuurate
Most online sources of time are what are known as stratum 2 time servers. This means they get their time from another time server (stratum 1) that it connected to an atomic clock (stratum 0). If there is an error with the stratum 1 device the stratum 2 device will be wrong (and every device that is trying to get the time from it).
The time server is leading to security problems with the firewall
Another common problem caused by the fact that all online time servers need access through your firewall. Unfortunately this gives the opportunity for malicious users to make use of this back door into your system.
Eliminating Time Server Issues
Internet time sources are neither guaranteed to be accurate, reliable or secure so for any serious time synchronisation requirements an external source of time should be used. NTP time servers that plug into a network and receive the time from GPS or radio sources are a much more secure and reliable alternative. These NTP servers are also highly secure as they do not operate across the Internet.