The choice of the switch, the Chengdu anti-theft system 1. The choice of the access layer switch The access layer switch is connected to the front-end network high-definition camera, and the convergence switch is connected to the Chengdu anti-theft system. The actual bandwidth of our commonly used switches is 60%-70% of the theoretical value, so the actual bandwidth of a 100M port is 50M-70M. Generally, 720P network cameras are calculated according to the 4M code stream, and a 100M access switch connects to 12 units to be 48M. At the same time, consider that the current network monitoring adopts the dynamic encoding method, and the peak value of the camera code stream will exceed 4M. At the same time, consider the bandwidth redundancy design, and one 100M switch should not carry more than 8 sets. In some ultra-high-definition network monitoring systems, in order to ensure the high-definition of the video screen, the access layer can also directly select a full gigabit switch. Since the price of gigabit switches and fast-megabit switches are almost the same, it is recommended to use gigabit switches directly, or the upstream port of fast-megabit switches is a gigabit anti-theft system. The access layer uses PoE switches as much as possible. 2. The choice of aggregation layer switches is still calculated by 720P network camera 4M code stream. Each access layer switch at the front end has 8 720P network cameras, and the aggregation switch is connected to 5 access layer switches. The total bandwidth of the aggregation switch is 4M*8*5u003d160M, so the cascade port of the aggregation switch and the core switch should be a gigabit port. The summary is: the aggregation layer switch is mainly connected to the access layer switch, and the core switch of the uplink monitoring center. The performance is higher than that of the access switch, and the aggregation switch needs to choose a Layer 2 switch with a gigabit upload port. The 100M port of the switch is connected to the access switch, and the Gigabit port is connected to the core switch of the monitoring center. The choice of aggregation switch is a switch with linear transmission. 3. The choice of core switch The core switch is mainly connected to the aggregation layer switch, the video monitoring platform of the uplink monitoring center, storage server, digital matrix and other equipment, which are the core of the entire high-definition network monitoring system. When choosing the core switch, you must consider the bandwidth capacity of the entire system and how the core layer switch is configured improperly, which will inevitably lead to the inability to display the video smoothly. Therefore, the monitoring center recommends choosing a full gigabit core switch. If there are many points, you need to divide VLANs, and you should also choose a three-layer full Gigabit core switch. Generally, when there are 500 cameras, it is recommended to use a 10G switch for the Chengdu anti-theft system.