Network monitoring system in our security occupies an absolute position. In the high-definition network video surveillance system, customers often have a feedback of the delay, Caton and other phenomena, caused for many reasons, but in most of the situation, they are caused by unreasonable switch configuration resulting in insufficient bandwidth. The switch is an indispensable device for the whole system. Whether it is properly configured or not directly affects the later stability of the network monitoring system.

When selecting a switch, the backplane bandwidth and packet forwarding rate should be considered. The backplane bandwidth marks the total data exchange capacity of the switch. The higher the backplane bandwidth is, the stronger the ability to process the data. Packet forwarding rate also known as port throughput refers to the packet forwarding capacity of the router in a port. The higher the packet forwarding rate is, the better the performance.

From the network topology, a large-scale high-definition network video surveillance system needs to adopt three-tier network architecture: access layer, convergence layer, and core layer.

1. Selection of access layer switch 

The access layer switches are mainly connected to the front-end network high-definition cameras, and connected to convergence switches. According to the calculation of 4M stream in 1080P network camera, how many 1080P network cameras can a 100 megahertz access switch access up to?

The actual bandwidth of our commonly used switches is 50% -70% of the theoretical value, so the actual bandwidth of a 100 megahertz is 50M-70M. Because 4M * 12 is equal to 48M, it is recommended that a 100 megahertz access switch maximizes to access up to 12 1080P network cameras. At the same time, consider the current network monitoring using dynamic coding and the camera code stream peak may exceed 4M bandwidth, while considering the bandwidth redundancy design, so it is best to control a 100 megahertz access switch to access up to 8 or less. And it is also recommended using Gigabit mouth if it is more than 8. In some ultra-high-definition network monitoring system, in order to protect the high-definition of video screen and high-reliability of data transmission, the full Gigabit switch can also be selected directly in the access layer.

2. Selection of convergence layer switch

Convergence layer switch is connected to the access layer switch, with the uplink of monitoring center core switches. Its performance is higher than that the access switch requires. Under normal circumstances, as for the convergence switch, Gigabit uplink Layer 2 switch should be selected. The switch’s 100 megahertz port is connected to the access switch and its Gigabit port is connected with the monitoring center core switches. The number of interfaces on the convergence switch should be controlled within 30.

3. Selection of core layer switch 

Core layer switch, mainly connected to the convergence layer switch with the uplink of monitoring center video surveillance platform, storage server, digital matrix and other equipment, is the core of the entire high-definition network monitoring system. In the choice of the core switch, consider that the bandwidth of the entire system capacity and how improper the core layer switch configuration is that inevitably leads to no smooth display of video screen. Therefore, the monitoring center suggests selecting the full Gigabit core switch. If with more points, you need to divide VLAN, choose three full Gigabit port core switches. If the number of cameras is more than 150,  large-scale monitoring system should consider three-tier Gigabit switch.

4. Focus when selecting switches 

In the switch selection of LAN video monitoring, because the main pressure is in the convergence layer switches which have to bear the storage traffic of the monitoring, but also bear the pressure to view calling monitoring at real-time. So it is especially important to choose the applicable convergence switch. It is recommended to select Gigabit managed switches, which can have the network configured to optimize the utilization of bandwidth and ensure the smoothness of transmission.