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NTP Network Time Server FAQ

Why Do I Need A Network Time Server?

Computers have notoriously inaccurate clocks. They often use cheap, inferior, crystals and clock components. After a relatively short period of time, the clocks of two or more computers will significantly differ. For transaction processing, trading, data logging, and many other applications a consistent network time is imperative to ensure correct operation. A local dedicated network time server is the best solution.

Why Not Use Public Internet Time Servers?

The are a number of public time servers available on the Internet that can be used free of charge. However, in order to access them, a port needs to be left open in the network firewall. This can introduce security risks. Secondly, timing accuracy can be significantly degraded by hundreds of milliseconds due to network latency. Also, many internet time servers are incorrectly configured and can potentially provide your computers with incorrect time.

A dedicated time server which is under your control and inside your firewall provides a far more accurate, reliable and secure source of time.

What Is NTP?

NTP is an acronym for Network Time Protocol. It is a standard networking protocol for synchronizing the clocks of computers to a time reference.

How Accurate Is NTP?

TimeTools T-Series NTP servers synchronize to within a few microseconds of UTC time. Client computers on a Local Area Network (LAN) can typically synchronize to within 0.5 to 2 milliseconds.

What Is Holdover?

Some NTP servers, such as TimeTools T550, have built-in high-stability oscillators. This allows them to maintain a much more accurate time in the unlikely event of loss of GPS\GNSS signals. The T550 will maintain stratum 1 operation for 24-hours after loss of signal lock. A previous 24-hour continuous signal lock is required to enable this feature.

Can NTP Use Local Time?

NTP utilizes UTC time rather than local time. UTC time is the worlds standard time scale. Client computers maintain local time by automatically and seamlessly adding an offset to UTC time. Time zones and daylight saving is accommodated by the client computer.

What About Leap Seconds?

Leap seconds are periodically inserted to realign clocks with the rotation of the Earth. TimeTools T-Series NTP servers correctly warn of impending leap seconds. Additionally, leap seconds are automatically inserted without requiring user intervention.

How Far Can The Antenna Be From The Appliance?

TimeTools has pre-terminated cables of 10m, 30m 50m and 100m available off-the-shelf. Cable runs of 250m can be easily accommodated. Also, with the addition of a single GPS amplifier, cable runs of 430m are achievable. Alternatively for very long cable runs to 1km or for enhanced security purposes, we can provide GPS over optical fibre solutions.

What Is The Ideal Antenna Location?

The ideal location for a GPS\GNSS antenna is on a roof top with a full 360 degree view of the sky. However, TimeTools T-Series NTP servers operate down to a single satellite in view. Single-satellite operation provides good signal reception with an antenna mounted on the side of a building or in a window with a much reduced view of the sky. Additionally, the high-sensitivity receiver, in some circumstances allows indoor signal reception. Problems may arise with an indoor located antenna if the building is metal clad or framed. Metallic screening reflects radio signals causing reception issues.

How Many Clients Can I Synchronize?

The T-Series can synchronize up to 100,000 network time clients using the default NTP polling rate of 64 seconds, enough for the largest of networks. Reducing the client polling rate will increase the maximum number of clients still further.