Installing a NTP Server using a reference source radio

Network Time Protocol (NTP) is one of the oldest Internet protocols still in use, invented by Dr. David Mills University of Delaware, has been used since 1985. NTP is a protocol designed to synchronize the clocks of computers and networks through the Internet or local area networks (LANs).

NTP (version 4) can maintain time over the public Internet for less than 10 milliseconds (1/100th of a second) and maybe even better on LAN with accuracies of 200 microseconds (1/5000th of a second) under ideal conditions.

NTP works within the TCP / IP and UDP on the basis of a less complex form of NTP exists called Simple Network Time Protocol (SNTP) that does not require the storage of information about previous communications, needed to NTP. E 'used in some devices and applications where high accuracy timing is not so important.

Synchronization with NTP is relatively simple, it synchronises time with reference to a reliable source of clock. This source can be relative (a computer's internal clock or time on a clock) or absolute (UTC - Universal Coordinated Time - clock source that is accurate as is humanly possible).

E 'strongly recommended by Microsoft and others, that the timing of external funds should be used instead of the Internet because it can not be authenticated. Specialist NTP servers are available that can synchronize the time on the networks using the MSF (or equivalent) or the GPS signal.

Atomic clocks are the most absolute maintenance devices, but are very expensive and are usually only found in a physics laboratory scale. However, NTP can synchronize networks of an atomic clock, using the Global Positioning System (GPS) network or specialist radio transmission (MSF Italy).

The period of national and radio frequency used MSF to synchronize an NTP server is published by the National Physical Laboratory in Cumbria which serves as the national reference time of the United Kingdom, there are also similar systems in Colorado, USA (WWVB) and the Frankfurt in Germany (DCF-77).

A radio based NTP time server usually consists of a rack-mountable server time and an antenna, consisting of an iron bar in a plastic bag, which received the broadcasting time and frequency radio. The antenna should always be mounted horizontally, perpendicular to the transmission of the signal optimally. The data is sent in pulses, 60 of a second. These signals provides UTC time to an accuracy of 100 microseconds, however, the radio signal has a limited scope and is vulnerable to interference.

Radio time server reference is easy to install and can provide an organization with a precise reference for the synchronization of networks around the