Network monitoring system is a revolutionary technology. It uses the standard TCP / IP protocol in computer network and Internet communication to form a video stream, which is transmitted in a wired or wireless network, and can be integrated with other network applications into a whole system. The network video surveillance system uses standard LAN / MAN / WAN / Internet as the core circuit for transmitting image, voice and data information. Network monitoring is based on the network, so the construction of campus network and the network of security monitoring have a direct relationship. At present, the school's campus network construction includes four parts. The first is the campus internal LAN, with computer-aided instruction (CAI), office automation (OA), intra-school information publishing and sharing, various professional and college LANs as the core and distinctive A comprehensive system with the characteristic computer campus culture as the goal. Secondly, it is a special education network, that is, a nationwide private network for academic computer interconnection operated by Education Network (China Education and Research Computer Network) CERNET, mainly for education and scientific research units, to carry out academic exchanges and seminars. The third is the Internet, usually through CERNET as an outlet, or directly rent a dedicated line to connect to the Internet, show the outside world the image and strength of the school, obtain outside teaching resources, and carry out some distance education, training and other social activities. The fourth is a comprehensive management auxiliary application system network, that is, a dedicated system network such as security monitoring network, campus card, telephone network, and ATM voice teaching examination network. In the dedicated system network of the fourth part, the video surveillance system occupies larger network resources. In order to build an efficient, smooth, and high-definition security system, transmission is a headache for the school. Build a dedicated monitoring network to solve transmission problems Security monitoring has unique characteristics of security and confidentiality, which can only be used and regulated by the school security department and relevant leaders. Ensure that the system operates normally without interference from the outside world. The video private network is the "neurology" of the network monitoring system, which ensures the stability of the system and is also the basis for the continuous expansion of the network monitoring system. At present, most schools have built campus networks and have loaded normal data application systems. However, in the security system, especially the network video signal is quite different from the daily data. It has the characteristics of uninterrupted, continuous, and large data packet transmission. Once a network failure occurs, it will cause video interruption and video loss. , Will directly affect the daily monitoring and video forensics. If an abnormal situation occurs at this time, the loss may be immeasurable. However, it is also because most campus networks are already in normal operation. Therefore, many school network security systems will first choose to expand applications based on the existing network, that is, the use of campus public networks for monitoring system construction. The advantage is that it can save the investment cost of building a private network, but many hidden network risks exposed, such as lack of network resources, malicious destruction of school employees and students, heavy system troubleshooting and maintenance, and because all security system application terminals are close to users The usage habits all use the WINDOWS operating system, so there will be viruses and Trojans in the process of information exchange. These problems will directly lead to the gradual paralysis of the monitoring system, and will also affect the normal operation of other application systems in the network. It was originally a cost-saving approach, but it became a perceptual investment that cost money to find trouble, and it is not worth the loss. In particular, the current campus security incidents have occurred frequently and the consequences are extremely bad. The education department and all sectors of the society have also paid attention to the safe campus unprecedentedly, and have successively issued relevant guiding policies and regulations, making the network monitoring system increasingly large-scale and standardized, and showing Unprecedented urgency. Therefore, through the construction of a dedicated security monitoring network to ensure the safe and stable operation of video surveillance, alarm, access control and other systems, it is the best choice for many school users. Although the initial investment is relatively large, but comprehensive consideration of input and output efficiency, you can In the future, it will reflect the economic and scalability advantages of the system. Analysis of networking mode The management centers of the three systems of video monitoring system, alarm and access control are usually set in the monitoring center. Compared with video monitoring, the latter two occupy a very small bandwidth. The alarm and access control subsystem only needs to connect the alarm host and the access control management host. Just connect to the private network. University users in Beijing, Shanghai, Northeast, Guangdong and other regions have almost all selected the construction concept of the security monitoring special network design, and the effect is remarkable. At present, the construction of the monitoring private network is still based on the general-purpose Ethernet. The private network system is built with a tree-shaped network structure, and the hierarchical network management and load balancing are realized through the three-layer mode of core, aggregation, and access. The comprehensive consideration of the construction of a special security network is carried out from two aspects. First of all, multiple network application systems, mainly including network video surveillance, alarms, network access control, and some schools need to access the local public security alarm center, and even fire protection systems, etc., showing more and more integration needs. To improve the interoperability and efficiency between systems, this requires a common network foundation, otherwise the connection between different networks also requires a lot of equipment and technical costs. Secondly, the maturity and stability of network transmission technology, as well as the optimization of video compression technology, combined with network transmission quality control technology, as long as the private network resources can be prevented from being illegally occupied, it can meet the current high-definition video transmission bandwidth requirements. Considering the future system integration and application expansion, it is only necessary to optimize and upgrade the core equipment. Of course, school users' understanding and preference of network technology has also promoted networks such as EPON and ATM to enter the security monitoring system to a certain extent. EPON is a shared media transmission method using wavelength division multiplexing technology. In a large-scale high-definition surveillance system, application solutions and technical optimization are not mature, which will cause bandwidth bottlenecks in the video transmission process. ATM is a transmission method that uses asynchronous time division multiplexing technology, and uses fixed cells for data processing. Coupled with the high cost under high bandwidth requirements, it is also not suitable for data transmission in which the video signal changes in real time. Therefore, the Ethernet networking method is still the most suitable, mature, and stable security private network construction method. However, there must be a premise that the network industry itself is a mixed free market, and the selection of network products with guaranteed performance is the key foundation. The selection of network products is based on two requirements, the first is performance requirements, including backplane bandwidth, packet forwarding rate, concurrent traffic processing, port configuration, optimization strategy, etc. On the other hand, it is the product's own stability requirements, including product quality and Factors such as actual industry application experience are used as selection criteria. Especially with the high-definition network video surveillance system, due to the larger code stream of each video, the transmission requirements are correspondingly higher. The network needs to be selected according to the actual access, aggregation, core transmission processing bandwidth and redundant bandwidth requirements of the high-definition surveillance system. product. Pen Case,Pencil Case Pouch,Pencil Case,Dinosaur Pencil Case Dongguan Mingpin Traveling Appliance Company , https://www.mpluggage.com