A GPS time server is ideal for preventing costly leap seconds that interrupt businesses that operate on a global timescale.
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.
Time synchronization is a crucial aspect of computer networking. Ensuring all machines on a network are synchronised to the global timescale, UTC (Coordinated Universal Time), otherwise time sensitive transactions with other networks would be impossible.
Time synchronization is made easy thanks to the Network Time Protocol (NTP) which was devised in the early days of the Internet for that very purpose. It works be utilising a single time source (usually UTC) which is then distributed amongst all devices on the NTP network.
The UTC time source is often taken from the Internet on networks where security is not a great issue but as this involves leaving an open port in a network firewall for many networks the vulnerability this can leave isn’t worth the risk.
Dedicated network time servers (often referred to as NTP servers) are used by many networks as a secure and even more accurate method of receiving UTC. These devices receive the UTC time direct from an atomic clock source.
Furthermore, these dedicated time servers operate external to the firewall and network and use sources such as GPS or radio frequencies to pick up the time codes.
For ease of synchronisation there are various time synchronisation software packages that run hand-in-hand with NTP and allow, through browser interfaces, easy configuration of the time synchronization throughout the network.
Whilst these time synchronisation software packages aren’t essential in using most NTP servers, the standard software installed in operating systems is often lacking or quite complicated.
Most specialist producers of dedicated network time servers will produce a times service client to allow configuration and these are probably best suited for the device from that suppler. However, there are many freeware and open source time synchronisation software packages that are mostly compatible with many NTP servers.
Windows 7 is the very latest operating system from Microsoft. Replacing the rather disappointing Windows Vista, Windows 7 promises to correct the flaws that made its predecessor so unpopular.
One of the changes Windows 7 makes is that it automatically synchronizes the time using the Windows Time service located at windows.time.com. Whilst this is an accurate stratum 2 time server, managed by Microsoft, it can be changed for another source of Internet time. However, even Microsoft recommend that Internet time sources should not used for computer networks as they can’t be authenticated by the time protocol NTP (Network Time protocol). Furthermore, an internet time source needs a port left open in the firewall for the time signals to make it through. Any open port in a firewall can be used by a malicious user to gain access to the network.
For a secure, authenticated and accurate method of synchronizing a Windows 7 network, then it is wise to use a dedicated network time server. Most of these time servers use the protocol NTP (Network Time Protocol) which can easily distribute a single time server throughout a network of hundreds and even thousands of machines.
Time servers plug directly into the router/switch for the network or can be installed on a single machine. Rather than rely on the Internet for a source of time and risk leaving the firewalls UDP port open, dedicated NTP time servers use either the GPS signals or long wave radio broadcasts transmitted from national physics laboratories such as the MSF signal broadcast by the UK’s NPL and the USA WWVB signal broadcast by NIST.
As these signals are external to the firewall and are able to be authenticated by NTP to establish the authority of the signals and are a more accurate and secure method of synchronizing a Windows 7 network.
When we consider the most important inventions of the last 100 years, very few people will think of an atomic clock. In fact, if you ask somebody to come up with a top ten of inventions and innovations its doubtful if the atomic clock would figure at all.
Its probably not hard to imagine what people think of as the most life-changing inventions: the Internet, mobile phones, satellite navigation systems, media players etc.
However, nearly all theses technologies rely on accurate and precise time and they would not function without it. The atomic clocks lies at the heart of many of the modern innovations, technologies and applications associated with them.
Let’s take the Internet as an example. The Internet is, in its simplest form, a global network of computers, and this network spans time zones and countries. Now consider some of the things we use the Internet for: online auctions, Internet banking or seat reservation for example. These transactions could not be possible with precise and accurate time and synchronisation.
Imagine booking a seat on an airline at 10am and then another customer tries to book the same seat after you on a computer with a slower clock. The computer only has the time to go on so will consider the person who booked after you to have been the first customer because the clock says so! This is the reason any Internet network that requires time sensitive transactions is connected to a NTP server to receive and distribute an atomic clock time signal.
And for other technologies the atomic clock is even more crucial. Satellite navigation (GPS) is a prime example. GPS (Global Positioning System) works by triangulating atomic clock signals from satellites. Because of the high velocity of radio waves an inaccuracy of 1 second could see a sat-nav device out by 100,000 km.
Other technologies too from mobile phone networks to air traffic control systems are completely reliable on atomic clocks demonstrating how underrated this technology is.
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.