Shulou(Shulou.com)06/02 Report--

The content of this article mainly focuses on what is the new function of ntp network time server. The content of the article is clear and clear. It is very suitable for beginners to learn and is worth reading. Interested friends can follow the editor to read together. I hope you can get something through this article!

Ntp network time server has a new function.

The ntp network time server relies on the GPS clock server to obtain the standard clock signal information from the GPS geosynchronous satellite through the GPS antenna, and then on the basis of the NTP protocol, the network time service system transmits these clock information in the network, and the devices that need the clock signal in the network, such as computers, can synchronize with the standard clock signal.

At present, the typical application of NTP protocol is to use NTP protocol to synchronize the clock of the computer equipment involved in the local area network, and to establish the same network clock together with the network switching equipment. The same network can be composed of a primary clock server, a secondary clock server, a client and the interconnected transmission routes between them. The master clock server's direct reference clock is usually the GPS satellite positioning system. The secondary clock server synchronizes through the main clock server in the network, and the secondary clock server transmits the clock information to other hosts in the local area network through the NTP protocol.

First, pay attention to the implementation when using

The main results are as follows: (1) GPS antenna is a passive antenna, which is the key component to ensure the synchronization of GPS receiver and satellite. Whether its erection is correct or not is directly related to the performance of GPS clock. In order to ensure the satellite collection effect of the GPS antenna, it should be installed as far as possible, such as the roof, roof, balcony, balcony and other places, as far as possible away from the emission source of the adjacent frequency point, to avoid the shielding of the antenna by buildings such as woods, floors and iron towers, and to stay away from high-voltage transmission lines and interference sources such as strong electric field and magnetic field. The antenna should be parallel to the horizontal plane and fixed on the base or bracket. note that when the antenna is installed on the roof, it should be lower than the height of the lightning rod.

(2) with the increase of the number of network layers, the time accuracy will decrease, and the total number of layers will be limited to 15 layers. In practical design and application, the number of stages should be reduced as much as possible. if there are too many layers, it will not only increase the complexity of the network, but also reduce the accuracy of time and the reliability of synchronization. We can layer according to the importance of time synchronization to the device.

(3) for prevention, NTP protocol also provides the function of authentication and encryption. If the network structure is not closed enough, the security of the time service of the core management equipment is very important, if it is affected, it will affect a wide range of services. Therefore, if necessary, the combination of timing verification requirements and access control policy can be used to prevent unauthorized access and changes to the core equipment, so as to ensure the accuracy, reliability and security of time in the network.

II. The uses and characteristics of ntp network time server

The output of ntp network time server generally has signal modes such as second pulse, minute pulse, time pulse, serial data and so on. The time service mode can be selected according to the accuracy needs of LAN equipment. For those whose time accuracy is less than millisecond, serial communication is generally adopted, and the satellite time is read by the host computer at regular intervals to correct its own time; when the time accuracy is less than millisecond, the pulse output signal can be used to correct the serial communication signal through hardware devices such as clock oscillation.

SYN2136 Beidou NTP Network time Server

Core functions:

1) establish time reference with GPS timing signal

2) provide 4 NTP network time service interfaces and 2 IRIG-B code signals

3) the front panel shows the year, month, day, hour, second, number of satellites and working status

4) support time synchronization in windows, LINUX, UNIX, SUN SOLARIS, IBM AIX and other operating systems

5) support NTP v1.v2.v3&v4 (RFC1119&1305), SNTP (RFC2030) and other protocols

6) support DHCP function, and all network devices connected to LAN port can obtain IP address automatically.

7) excellent security performance, providing firewall protection, enabling SYN-flood defense, greatly improving the security of the internal network and reducing risk

8) heartbeat detection is supported. Multiple time servers or network ports can be set to the same IP, which are redundant backups for each other.

9) Parameter management that supports WEB and SSH encrypted communication and software monitoring settings

10) support WEB firmware upgrade, provide parameter backup and import, system local log and remote log sending and other functions

11) provide software and hardware watchdog design, QoS function (traffic monitoring) and network diagnosis, etc.

12) Parameter settings files can be exported and imported

13) switch between Chinese and English on the network configuration page, setting username, password and hostname

14) Real-time monitoring of load, elapsed time, real-time traffic and memory status

15) display real-time links, including IP, communication protocols and interactive data volume of the time server accessed by the client, and display historical data in a graphical form.

Beidou high precision time-frequency server

As the name implies, the Beidou high-precision time-frequency server obtains a standard high-precision time information from the Beidou satellite, which is processed by internal high-tech technology. make the Beidou time information go to the departure time information and standard frequency information through other interfaces.

Time-frequency server component

The components of Beidou high-precision time-frequency server are: antenna, antenna installation bracket, mainframe, connection line.

Antenna: the antenna is also called time service antenna, satellite antenna and so on, which is used to obtain the standard time signal of the satellite and transmitted to the host through the cable medium. in general, the transmission distance is limited, standard 30 meters, if longer, need to do signal amplification processing.

Host: the host contains a Beidou receiver, and the standard clock information is obtained on the Beidou satellite through the antenna. After high-precision analytical processing of the chip and the motherboard, some standard time and frequency information is output through the host's NTP interface, PTP interface, serial port interface, B code interface, frequency output interface and so on.

Composition and use of gps time synchronization Server

Gps time synchronization server system is composed of equipment host and antenna.

1, gps time synchronization server is a gps satellite to obtain time, the time information has been processed through a certain interface (network port, serial port, irig-b code, 1PPS, etc.) output, so as to other equipment for time calibration, the use of each interface is not the same, detailed usage, please contact our company sales staff.

2. The time service antenna refers to receiving the carrier signal transmitted by the satellite, and using the time service antenna to obtain the standard time information of the satellite. The time service antenna is a kind of receiving device that receives the satellite carrier signal, and then processes the acquired signal, transmits it to the host computer for processing, and then outputs various interfaces. The time service antenna should work reliably to reduce the influence of the environment and the surrounding electromagnetic / radio waves. therefore, the lightning protection design and anti-interference design of the time service antenna must be taken into consideration.

3. Before the fixed installation of the antenna, it is recommended that the user should first test the satellite signal and antenna. After obtaining the satellite signal normally, confirm that the antenna does not have any satellite collection problem, and then go upstairs to install it. In order to correctly determine whether it is a host problem or an antenna problem.

4. the time service receiving antenna shall be installed outdoors, such as balcony / balcony / roof, and there is no electromagnetic / radio wave interference in the surrounding space, and the field of view of the white mushroom head at the top of the antenna should not be a piece of obstacles such as buildings, woods, signal transmission towers, etc., so as not to block the reception of satellite signals, and the power required for the antenna is provided by the local machine through the antenna feed line (coaxial cable).

Time server structure

The system built by gps network time server is mainly composed of GPS satellite antenna, time server host, switch, client terminal and so on.

2.1GPS satellite antenna

GPS satellite antenna is to receive time signal and positioning signal from satellite. GPS satellite signal is divided into L1 and L2, in which L1 is an open civil signal. The length of the antenna is generally 30, 50, 80, 100, 150, 200 meters and so on, which is chosen by the customer according to the actual situation.

2.2 time server host

The time server receives the satellite signal through the GPS antenna. After high-tech processing and calculation, the time server sends out NTP v1.v2.v3&v4 (RFC1119&1305), HTTP/SSL/HTTPS (RFC2616), 802.11b RFC2030, SNMP,SSH/SCP,MD5 (RFC1321) IPV4, IPV6, IPv4/IPv6 Hybrid,Telnet (RFC854), NTP Unicast,Broadcast,Multicast and other protocols through the network port (RJ45 port). It is commonly used to provide time service to computers, cameras, NVR, servers and other common customer terminals. The built-in GPS receiver in the time server is the core component of the GPS receiver. The GPS receiver receives the satellite signal. The GPS signal includes two kinds of carriers (L1, L2) and two kinds of pseudo noise codes (P code, Chand A code). The data received by the satellite receiver is modulated by the pseudo noise code of the United States, and then the noise code is modulated on the carrier. In fact, we use Cramp A-rough code, which can be used free of charge all over the world. P code is accurate and is not open to civilian use. After receiving the satellite signal, the internal hardware circuit and software of the receiver can extract and output two kinds of time signals by decoding and processing the received information: one is the synchronous pulse signal 1PPS with an interval of 1s (the level is 3V), and the other is the serial time information, which corresponds to the 1PPS pulse.

2.3 switch

When the network port of the time server is connected to the switch, the switch can divide an input network port into multiple output network ports for use by the terminals below. If one switch is not enough, dozens of switches can be used for expansion.

2.4 customer Terminal

Client terminals refer to the terminals that users need to synchronize, such as computers, cameras, NVR, servers and other common client terminals that need time service, and so on.

III. Analysis of time service agreement

There are three main time code protocols currently in use: Daytime (RFC-867), Time (RFC-868) and Network Time Protocol. Network time protocol is the most complex, advanced and high-precision time code protocol at present. Among them, SNMP and TNMP are two widely used network time code protocols. Install the network time server software on the time server and install the NTP client software on other computers in the local area network. The client software can run continuously and periodically as a background task, and constantly get the updated information of the server.

Advantage analysis

By using the satellite time synchronization system of NTP, the high precision time information is obtained through GPS or Beidou navigation equipment terminal, and the time information is provided to the local area network integrated system as a time source, which can ensure the accuracy of the time source of the local area network system. At the same time, the time synchronization between the test equipment in the same network segment is realized in the form of UDP multicast. The NTP time synchronization principle is applied to realize the time synchronization between the cross-network segment test equipment in the form of UDP client, which not only considers the efficiency of the system operation, but also meets the requirement of accurate milliseconds of the satellite integrated test system, and can effectively solve the time synchronization problem of the integrated test system in the wide area network environment, which can not be realized by the existing integrated test system time calibration software.

The GPS receiving device is used to receive the GPS information and connect with the server to correct the time of the clock source server.

The timing terminal periodically sends NTP packets to the timing server to request the time reference clock. After obtaining the reference clock, the computer system clock is corrected by the application software to synchronize it with the clock of the time service server.

Thank you for your reading. I believe you have a certain understanding of "what is the new function of ntp network time server". Go and practice it. If you want to know more about it, you can follow the website! The editor will continue to bring you better articles!

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.