Atomic clocks – the key to network synchronization
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Sourcing the right time for network synchronization is possible only thanks to atomic clocks. Compared to standard timing devices, and millions of times more accurate atomic clock with the most innovative design is the exact moment one second in 100,000 years.
Atomic clocks use the constant response of the atoms in different energy states, the time to measure the performance of a nuclear tick that occurs almost 9 billion times per second, in the case of a cesium atom. Indeedthe resonance of cesium is the official definition of a second has been adopted by the International Unit (SI).
These clocks are the basis for the international use of time, UTC (Universal Time Coordinated). And also the basis for the NTP server to synchronize the time, computer networks and technologies, like the other by air traffic control and high-level time-sensitive applications.
Finding a source of atomic clock Clock is a simpleProcedures. Especially with the presence of sources that are at the time when Microsoft and supplied by the National Institute of Standards and Time (windows.time.com and nist.time.gov).
However, these NTP servers are what are known as the middle layer 2 devices that are to any other device, which is now the time to an atomic clock (in other words, a second-hand source is connected to the clock).
While the accuracy of this layer-2 server is not a question of them may be influenced bythe distance between the client-server since they are outside the firewall means that any communication requires a server-time online is an open UDP (User Datagram Protocol) port to allow communication.
This can cause failures in the network and not used for this reason, any system that requires a complete security. A secure (and reliable) method of receiving Clock is an NTP server to use. To receive this time of synchronization devicesthe time from atomic clocks, either directly broadcast on long wave from places such as NIST or NPL (National Physical Laboratory – UK). Alternatively, the clock can be started from the GPS signal through the constellation of satellites in the GPS network (Global Positioning System Broadcast derivatives).
Atomic Clock Systems
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An atomic clock that provides a very accurate source of time. There are different types of atomic clock, which is located mostly in the laboratory: cesium clocks, watches, hydrogen and rubidium clocks. Longer commercially available systems atomic clock synchronization using a radio or GPS time signal that a precise time reference rate of interest is bound. In this way, a very accurate source of time is readily available for users of all days, excluding the costs of installing expensive and complexEquipment.
This article provides an overview of atomic clock systems with particular emphasis on their use with NTP server systems for PC and network synchronization of computer time.
Atomic Clock Radio
References Time Radio broadcasts time as MSF-60 (UK), the DCF-77 (Germany) and WWVB (U.S.) time to transmit signals accurate time information from a radio transmitter. The transfer time is derived from a reference atomic time clock and canreceived from the timing with a radio-receivers at low cost. MSF-60 radio signal from Rugby in the UK, with coverage of the British Isles and throughout most of North-West Europe transferred. The DCF-77 from Frankfurt, Germany, transfer, and covers most of central Europe. While the WWVB signal in Fort Collins, Colorado, United States transferred.
MSF-60 time of transmission
MSF-60 time signal is a longwave time signal transmitted at 60kHzRugby in the United Kingdom. The radio signal is received by BT Engineering Services. MSF-60 Time of the signal is extremely accurate atomic clocks at the National Physical Laboratory (NPL) is generated. When decoded, provides a very precise timing reference clocks for NTP time servers and other equipment.
DCF-77-Transmission
The DCF-77 radio-wave clock signal is transmitted from a signal at 77.5 Mainflingen, near Frankfurt,Germany. The radio signal is maintained by T-Systems, a division of Deuche Telecom and in operation since 1959. The DCF-77 highly accurate atomic clocks German National Physics Laboratory is generated. When decoded, provides a very accurate timing reference for clocks and computer timing equipment.
WWVB transmission time
The WWVB time signal continuously transmits signals in time and frequency at 60 kHz from Fort Collins,Colorado, USA. The time reference is received from the U.S. National Institute of Standards and Technology. WWVB continuously transmits time and frequency since 1962 made available. The signal is a time reference with an accuracy of less than 100 microseconds.
GPS Time Atomic Clock Reference
The Global Positioning System (GPS) is a U.S. military for navigation around the world. The system consists of 24 satellites in orbit, each satellite has an extremely accurate atomic clockOn-board UTC time synchronized. The satellites continuously transmit time and position data. The timing and location information can be obtained throughout the world with a GPS receiver and antenna. GPS works continuously, whether the conditions for everyone, everywhere in the world. In addition, there are no set-up fee or subscription charges to use GPS systems. Timekeeping systems Many computers and NTP server systems for use as a precise timing reference external GPS. GPS timing is usuallymuch more accurate than the baseline time radio.
Computer Time Synchronization
Computer time synchronization can be achieved by combining a precise timing GPS receiver and radio with RS232 or USB interface to achieve. Driver software can be installed on the host PC to obtain the correct time and the host PC, synchronize the system time. Most PC operating systems can be synchronized, including Microsoft Windows 2000, 2003 and XP, Linux, Unix and Novell. In different casesthe time of the host PC within a few microseconds, the time synchronized.
Network Time Synchronization
The standard protocol for the implementation of the network synchronization of the computer time is the Network Time Protocol (NTP). NTP is the standard way to distribute the time on the Internet and other networks. Stratum 1 NTP server to receive an external reference time, such as GPS, MSF-60, DCF or WWVB-77. Time external referenceis then used to set the NTP server to synchronize the system time. The time synchronized system is then used by the NTP server to distribute the correct time to time the network client on an IP network. NTP is a hierarchical way, less time to NTP server to get to higher-level devices.
NTP server systems can be synchronized to less than a few microseconds, at the right time. Depending on network traffic to synchronize NTP client, with someMilliseconds, an NTP server.
Computer-network 