The devices in LAN have their own time. Each device can be adjusted according to the clock time and manually adjusted to achieve network time synchronization. This method does not require additional development of software and hardware, and can be completed by using existing equipment. But the time synchronization accuracy is low, and the error can reach several seconds, resulting in the time error between devices.

However, due to the physical isolation of the local LAN and the Internet due to the need of information security, the network devices in the local area network can not provide time service through the Internet. This leads to the fact that the time of several devices in the same information system is not uniform and inaccurate. Such as NTP time synchronization server GPS time service and domain management can avoid this problem very well.

NTP network time synchronization technology can transmit the standard time data packets in the network by broadcasting, and the time synchronization devices in the network are required to set up the operation system accordingly, so that the time synchronization can be automatically synchronized to the NTP time server, so as to achieve the time synchronization of the whole network. This method is simple and does not need to compare with the clock surface.

The completion time unified work is inseparable from the two important parts of timing and timing. The process of transmitting time information to a user in a wired or wireless way is called time service; the process of receiving the standard time signal and making the local time consistent with the standard time sent by the time table is called timing.

The calibration of the time information of all kinds of communication equipment or computer equipment on the network is in a small enough range. This synchronization process is called network time synchronization. Network time synchronization is a time service method for users to access standard time through time service software.

GPS timing is mainly composed of Ethernet transmission module, main controller module, RJ45 interface transmission module, and time information collection module. After receiving the satellite signal processing, the main controller receiver is transmitted to the client equipment which needs time to be transmitted through the Ethernet transmission module.

GPS timing equipment takes SYN2101 type NTP time synchronization server as an example. It has many advantages, which can be summarized as follows:

The timing accuracy is high, the timing internal timing accuracy of the server can reach 30ns, and the network timing accuracy is about 1-10ms under different network environments. The time error between multiple clients can be less than 2ms. The timing of Wan is supported by 50ms.

Support cross network segment time service, time synchronization server and network computer equipment, the normal network is originally isolated network segment, if the network environment of the scene can support cross network segment access to a device, time synchronization server can also. Otherwise, just like a switch, 2 computers can set up different network segments, so that there is no way to communicate normally.

The user capacity is large, the time synchronization server throughput is up to 4000 times /s, the configured time synchronization server throughput can reach 14000 times /s, throughput is also able to support so many devices per second and request time to the server. In fact, there are not so many devices that can be requested at the same time in practical application. In theory, time synchronization server 1 NTP network port can support tens of thousands of devices to give time, such as tens of thousands of devices at the scene, it is recommended to expand to 2 or 4 network outlets output.

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