Coordinated Universal Time or UTC is now the world’s time standard it took over from the old Greenwich Meantime (GMT) after the development of atomic clocks. UTC is based on GMT but accounts for the random variations of the Earth’s rotation by having leap seconds added once or twice a year.

By accounting for the Earth’s rotation, UTC can keep noon above the meridian line (as GMT) but can also be recorded by the highly accurate atomic clocks.

UTC is ‘Universal’ in that it allows the entire world to communicate with the same timescale. For us humans UTC accounts for the time-zones by having a positive or negative integer after the time. Here is the UTC time zones:

Fortunately computers aren’t bothered about timezones and when communicating together across global networks via a time server UTC is the same no matter where they are on in the world.

Computer time servers usually receive their UTC time from a source external to the internet such as the GPS signal which are directly broadcast via atomic clocks in doing so a time server can keep a computer network to within a few milliseconds of UTC.

Time servers are incredibly important but an often overlooked part of a computer network. They are essential devices ensuring that all computers and devices connected to the network are synchronised to the same time. This prevents any problems from occurring when networks run sporadic time such as emails arriving before they were sent or even more serious security issues.

Time servers are similar to other servers but their sole role is to receive the time from a trusted source and distribute it amongst the network. The network time server can receive this time source from several places but in doing so one must have in mind two questions: How accurate is the time reference supplying the time? And how secure is it?

There are two highly accurate and completely secure methods of receiving the time for a time server. Both methods supply UTC (Coordinated Universal Time) which is a global timescale maintained by highly accurate atomic clocks. The first is to utilise the Global Positioning System (GPS) whose satellites all have onboard an atomic clock or the second is to use the national physics’ laboratories time and frequency transmissions.

Once a timing reference is received it is distributed to machines on a network using the protocol NTP (Network Time Protocol). NTP is based on an algorithm that not only corrects the time on any device but also ensures that the UTC time being received is secure, stable and precise.

NTP is one of the oldest Internet based protocols having been around since the 1980’s yet it is a testament to its developers that over twenty years on it is not only still in use but is by far the most common time protocol in use.

A time server is an integral part of any network system. It ensures all machines on a network or keeping the exact same time, failure to do so could lead to all sorts of problems, particularly with time sensitive transactions.

Most computer networks are synchronised to UTC (coordinated Universal Time). UTC is a global time scale and used throughout the world. It is also highly precise as it is based on the time told by atomic clocks.

Atomic clocks are ideal sources of time as they do not drift whilst the standard electrical oscillators on our PC clocks can drift by a second every week. This drift can cause untold problems which is why most networks are synchronised to a time server that receives a time signal from an atomic clock.

Atomic clock time signals can be received from a myriad of sources. The Internet is an obvious choice but unless security and precision is not an issue then it is not recommended for any commercial networks as using an Internet times source can leave a system open to security threats.

For security and accuracy there are two options to synchronise to an atomic clock. One is to use a GPS time server that receives the time-code from the GPS system. The other method is to use a time server that can receive the long wave radio transmissions broadcast from several national physics laboratories.

Physics laboratories across the globe transmit UTC (Coordinated Universal Time) radio broadcasts that can be received using a radio referenced time server. These time signals are an accurate and secure method of receiving UTC time.

Whilst many of these signals only have a limited range and are only available for certain periods several most notably the USA’s WWVB, Germany’s DCF and the UK’s MSF signals -provide a continuous and widespread broadcast that can be received 24 hours a day and even in neighbouring countries.

Here is alist of many of the World’s radio time server signals:

Table courtesy of the World Radio and TV Handbook.

NTS-8000-GPS

NTP Time Server with dual GPS and radio (MSF/DCF/WWVB) receiver

The Galleon NTS-8000-GPS Network Time Server combines a GPS based atomic radio clock with a radio receiver allowing dual signals to be received. The radio receiver can be tuned for either MSF(UK) WWVB (USA) or DCF (Germany). The NTS 8000 comes complete with Windows operating system based computer and offers straight forward configuration and management via the standard Windows interface using a keyboard and screen or remote access and connects directly to Ethernet, fitting in a standard 19″ rack.

NTS – 6000-GPS

NTP Time Server with integrated GPS receiver

The Galleon NTS-6000-GPS Network Time Server combines a GPS based radio clock with an embedded Linux solid state computer and offers straight forward configuration and management via a browser interface.

Connects directly to Ethernet and fits in a standard 19″ rack. The NTS 6000 incorporates a Galleon GPS Computer Clock which tracks up to 12 satellites. It comes complete with remote antenna that can be positioned up to 1,000m (3,000 ft) away with LCD signal strength display for easy installation.

NTS-4000- MSF/WWVB/DSF

NTP Time Server with integrated MSF/WWVB/DCF receiver

The Galleon NTS-4000- Network Time Server combines a radio receiver with an embedded solid state computer. It can be fitted with either a MSF/DCF o WWVB receiver module and offers straight forward configuration and management via a network interface.
Connects directly to Ethernet, fits in a standard 19” rack, 1U high and incorporates a Galleon Network time clock, with remote antenna that can be positioned up to 150m (450 ft) away as standard.  Conforms to Network Time Protocol Version 4 (NTP V4).

Galleon Systems and their The NTS 4000 MSF S and the NTS 4000 GPS S are possibly the two least expensive time servers available anywhere.

They are simple to use NTP time servers receiving accurate time from the a radio time signal (MSF) or the GPS network and using NTP can provide this synchronised time via a Ethernet port to any computer, server, switch, etc that conforms to the Network Time Protocol V3. And unbelievably they can process 1,000 NTP requests per minute.

The identical looking units are attractive pieces of kit too: