Year1
- 型号：
- W9001
- 规格：
- 2U19英寸
- 重量：
- 5KG
- , Introduction:
. - With the popularity of the Internet, many units have built their own campus networks, using more and more network equipment and servers. These devices have their own clocks, which can be adjusted. However, there is no guarantee that the time of all devices and hosts in the network is synchronized, because these clocks will have errors of several seconds or even minutes every day. After long-term operation, the time difference will become larger and larger. This deviation has little impact on a single machine, but may cause unexpected problems in applications in a network environment. For example, in a distributed computing environment, due to the inconsistent time of each host, the recording time of the same operation on different hosts will be inconsistent, which will cause the service to fail to proceed normally. With the continuous development of various network applications, time requirements are becoming higher and higher, and time inconsistency will cause many problems. The
timing server
independently developed and produced by Jinan Weishang Electronics Co., Ltd. - solves all these problems.
- ,
- Overview
- Convert the time information of various devices or hosts in the network environment
(
- Year, month, day, hour, minute and second< br/>)
- Based on
( )
- The time deviation is limited to a small enough range
(
- such as
)
- , this synchronization process is called time synchronization.
- Currently, there are two important time synchronization technologies, namely Network Time Protocol
( r
-,
)
- and direct connection time transmission technology. Among them, the direct connection time transmission technology requires all clients to directly connect to the standard time source, which is not practical.
- It is suitable for network environments and can provide accurate and robust time services in a disordered network environment, which is convenient and practical. Here we only discuss time synchronization technology and applications based on the
- principle.
- ,
- Working principle and application
3
- ,
- Overview of the protocol
-
- First developed by the United States
- Designed and implemented by a professor at the university, developed from time protocol,
- timestamp message and
- timestamp option.
- Used to synchronize the time of a computer client or server to another server or reference clock source. It uses
- as the time standard, is an application layer protocol based on the connectionless
-protocol and
-protocol, and uses a hierarchical time distribution model to achieve the most accurate The degree of dependence depends on the accuracy of local clock hardware and tight control of device and process delays. When configuring,
- Redundant servers and multiple network paths can be utilized to achieve high time accuracy and reliability. In practical applications, there is a simple network time protocol
( r
-,
)
- that ensures second-level accuracy.
3
-,
- Working principle
- Impact
- The most critical reason for protocol accuracy is the clock delay calculation caused by the randomness of network delay of inaccuracy. Because of the inaccuracy of latency, one-sided transmission from the time server to the client cannot be relied upon to deliver precise time information. To solve this problem, the concept of bidirectional information exchange between time server and client and timestamp
- is used in the
- protocol.
-
- The true clock deviation value is centered around the measured deviation value, and its possible range of variation is equal to the measured delay. Each
- message contains the latest
- timestamp, and the
-th timestamp is determined by the arrival time of the message. Therefore, both the server and the client can independently determine the time offset. The advantage of this symmetrical continuous sampling time transmission method is that there is no requirement for the order of messages sent and received, so a reliable transmission path is not required. Obviously, the final accuracy will depend on the statistical properties of the sending and receiving paths.
.
Timing server
- Application in campus network
- In our school campus network, there are a large number of network devices, servers and hosts, which carry Functions such as billing, maintenance, and management in campus networks have relatively high requirements for time accuracy, and require that information transmitted between networks be highly consistent in time.
-
Timing server
- The application in the campus network mainly focuses on the following aspects:
- Log audit of the network management system : When a malicious attack or network failure occurs on the network, the network administrator needs to analyze and make judgments based on the logs generated by the relevant network equipment in order to find the source of the attack and the harm to the network and its causes. However, if the time in the network cannot be synchronized, the logs generated by the same behavior in different devices will not be serialized, making it impossible to analyze and solve these problems. In addition, when the network management center adopts multi-point logging, if the time of each node in the network is not synchronized, it will also cause confusion in the log records. If this information is needed to quickly and accurately locate faults, accurate time is essential.
- Application authentication process: Some application systems in the campus network and the all-in-one card system to be built in the future require that the time in the network must be synchronized during user authentication. Because the digital timestamp service in authentication requires the client to use local time as a parameter to exchange authentication information packets with the authentication server. If time synchronization in the network cannot be achieved, the system will encounter problems and may be attacked during the authentication process.
- Time-related application systems: Network application systems that strictly require recording the time of data submission must ensure that the submission time is accurate and unchangeable. In addition, application systems that perform time-limited operations on clients also require time synchronization.
- Campus network backup system: Incremental backup between the backup server and the client requires time synchronization between the two systems.
- Ensure that remote system calls between systems can proceed normally: In order to ensure that a system call is not repeated, the system call is only valid within a time interval. If the clocks between systems are not synchronized, the system call may time out before it even occurs.
- Billing system: Digital timestamp services are also used in network billing systems, so precise time synchronization is also required.
- Various application systems, security systems, and network management systems in the campus network have promoted the demand for time synchronization of network equipment, servers, etc. If accurate time synchronization cannot be performed, we will have to spend a lot of time solving various problems that may arise.
- In short, time synchronization technology is very important for network management and network applications. In order to ensure time synchronization between various devices and systems in the campus network, it is necessary to deploy a high-precision
timing server
-.
- Standardized production process
,
- Strict product quality control
,
- Ensure that every piece of equipment produced by Weishang Company meets high precision and stability .
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