Types of Dedicated Time Server

Dedicated time servers are used despite the numerous Internet time sources available. The advantages of a dedicated time server is that the device is behind a firewall so preventing any security issues, dedicated time servers can also guarantee accuracy that is just not possible over the Internet.

The dedicated time server checks the time stamp from the UTC source (Coordinated Universal Time) and uses the information to calculate if the network clocks are drifting and adds or subtracts a second to match. The time server will do this at set intervals. Most time servers utilise NTP (network time protocol) although other protocols do exist NTP is by far the most widespread.

For NTP to distribute the time it first needs a timing source and this is where the differences in dedicated time servers come in. As UTC is based on the time told by atomic clocks, it is an atomic clocks that is the source for a time servers timing reference. Atomic clocks are extremely expensive, large, and require a multitude of maintenance engineers. For this reason they are only to be found in large scale physics laboratories.

However, the time from an atomic clock can still be utilised by using either a radio clock attached to a time server or a GPS clock. A radio clock is just a simple radio receiver that picks-up the long-wave signal broadcast by several national physics laboratories. This UTC signal is not available everywhere and the broadcast can be blocked by buildings, mountains and bad weather etc.

The other type of dedicated time server utilise the signals sent by the GPS satellites (global positioning system). These signals are available literally everywhere on the globe although the only downside is that a GPS antenna needs to have a clear view of the sky and therefore ideally needs to be situated on a roof which can cause some problems if the server room is along way from the top of the building.

Some dedicated time servers can actually receive both signals; the radio and GPS. In doing so they can continue receiving time signals even if one signal fails or gets temporarily blocked.

Common Time Server Questions

What is a time server?

A time server is a device that utilises a single time source and distributes it amongst a network. This enables all machines on a LAN (or WAN) to be synchronised together.

What is NTP?

Network Time Protocol is a protocol (a set of instructions) designed to distribute the time from a time server top a network.

Why do I need a time server?

It may well be that you don’t. Many small networks survive and operate perfectly without the need of a time server. However, if computers are required to do time sensitive transactions or applications then a time server is essential. Without proper synchronisation all sorts of unforeseen problems can arise and many of the online transactions that we take for granted such as seat reservation, Internet shopping, the stock exchange and even sending emails are reliant on perfect time synchronisation.

What is the best time reference to use?

A single global timescale based on the time told by atomic clocks has been developed called UTC (Coordinated Universal Time). UTC is utilised by networks all over the world. In using UTC you are in affect synchronising your network with every other network in the world that utilises UTC.

Where to I get UTC time from?

The most common and easiest location to receive UTC time is from across the Internet although Internet time sources are notoriously inaccurate. They also provide little security. Apart from the fact the time server is outside your firewall, NTP can’t authenticate these signals. Authentication is a security measure used by NTP to prevent malicious attacks that masquerade as a time server.
The most secure methods for receiving UTC time is by using either the GPS network (global positioning system), whose satellites transmit the timing information or alternatively by using specialist national time and frequency long-wave transmissions although these are not available everywhere.

Probably the most inexpensive time servers in the World!

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:

Time Servers – Using the MSF Broadcast

Time servers are essential in keeping computer networks synchronised without them many time sensitive transactions would be impossible to conduct. Time servers work by receiving a signal timing reference and distribute it to all devices on a network using the protocol NTP (Network Time Protocol). The time signal used by most time servers comes from a UTC (Coordinated Universal Time) source. UTC is based on the time told by atomic clocks and is used globally, allowing computers from across the world to be synchronized to the same time reference.

There are three methods that time servers can receive the UTC signal from. Firstly, the internet, although unsecured and without any guarantees of accuracy Internet time references are only suitable for networks where precision and security are not a concern.

The second method is via the GPS network which is available everywhere but only where an antenna has a clear view of the sky.

The third and simplest method to receive an accurate and secure UTC time reference is to use the national time and frequency broadcasts. In the UK the National Physical Laboratory transmits the British signal from Anthorn in Cumbria. This signal, known as MSF, can be received in most places in the UK although local topography can interfere with the transmission.

To receive the MSF broadcast a radio referenced NTP time server is required. This will receive the radio transmission via 65 kHz in long wave and distribute it amongst the network.
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. The antenna should always be mounted horizontally at a right angle toward the transmission for optimum signal strength.

Similar national timing transmissions are broadcast from other countries in the US the signal is referred to as WWVB and is broadcast by the NIST (National Institute for Standards and Technology) in Fort Collins, Colorado, other systems are broadcast in Frankfurt, Germany (DCF-77), Japan (JJY) and France ( TDF).

Using A Time Server to Maintain Precise Time on Your Computer

Computer networks rely on timekeeping for nearly all their applications, from sending an email to saving data, a timestamp is necessary for computer to keep track. All routers and switches need to run at the same rate, out of sync devices can lead to data being lost and even entire connections.

All PC’s and networking devices use clocks to maintain an internal system time. These clocks, called Real Time Clock chips (RTC) provide time and date information. The chips are battery backed so that even during power outages, they can maintain time.

However, personal computers are not designed to be perfect clocks, their design has been optimized for mass production and low-cost rather than maintaining accurate time. However, these internal clocks are prone to drift and although for many application this can be quite adequate, often machines need to work together on a network and if the computers drift at different rates the computers will become out of sync with each other and problems can arise particularly with time sensitive transactions.

For some transactions it is necessary for computers to be perfectly synchronised, even a few seconds difference between machines can have serious effects, such as finding an airline ticket you had booked had been sold moments later to another customer or you could draw your savings out of a cash machine and when your account is empty you could quickly going to another machine and withdraw it all again.

Time servers are like other computer servers in the sense they are usually located on a network. A time server gathers timing information, usually from an external hardware source and then synchronises the network to that time.

Most time servers use NTP (Network Time Protocol) which is one of the Internet’s oldest protocols still used, invented by Dr David Mills from the University of Delaware, it has been in utilized since 1985. NTP is a protocol designed to synchronize the clocks on computers and networks across the Internet or Local Area Networks (LANs).

NTP utilises an external timing reference and then synchronises all devices on the network to that time.

Often time servers are synchronised to a UTC (Coordinated Universal time) source which is the global standard time scale and allows computers all over the world to synchronised to exactly the same time. This has obvious importance in industries where exact timing is crucial such as the stock exchange or airline industry.

There are various sources that a time server can use as a timing reference. The Internet is an obvious source, however, internet timing references from the Internet such as nist.gov and windows.time can not be authenticated, leaving the time server and therefore the network vulnerable to security threats.