Switch selection and configuration in HD network monitoring

A medium and large-scale HD network video monitoring system needs to adopt a three-layer network architecture: access layer, convergence layer and core layer. Small network monitoring system shall adopt two-layer network architecture: access layer and convergence layer.

1. Selection of access layer switch

The access layer switch is connected to the network HD camera and the convergence switch. Taking the 720p network camera as 4m code stream, how many 720p network cameras can be connected to a 100m port access switch?

The actual bandwidth of commonly used switches is 50%-70% of the theoretical value, so the actual bandwidth of a 100m port switch is 50m-70m. 4m*12=48m, therefore, it is recommended that a 100m access switch be connected to a maximum of 12 720p network cameras. At the same time, considering that the current network monitoring adopts the dynamic coding method, the peak value of the camera code stream may exceed 4m bandwidth, and considering the bandwidth redundancy design, it is best to control one 100m access switch within 8, and it is recommended to use Gigabit access switches for more than 8, so as to avoid delay and packet loss caused by insufficient bandwidth.

2. Selection of convergence layer switch

The convergence layer switch is connected to the access layer switch and the monitoring center core switch. Generally, the convergence switch needs to select the switch with Gigabit upper interface.

Based on the 4m code stream of 720p network camera, there are 6 720p network cameras on each access layer switch at the front end, and the convergence switch is connected to 5 access layer switches. The total bandwidth under the convergence layer switch is 4m*6*5=120m, so the cascade port between the convergence switch and the core switch should be Gigabit.

3. Selection of core layer switches

The core layer switch is mainly connected to the convergence layer switch, and connected to the video monitoring platform of the monitoring center, storage server, digital matrix and other equipment. It is the core of the entire HD network monitoring system.

When selecting the core switch, the bandwidth capacity of the whole system must be considered. If the core layer switch is not configured properly, the video picture will not be displayed smoothly. Therefore, the monitoring center needs to select the full Gigabit core switch. If there are many points and VLANs need to be divided, three-layer full Gigabit core switches should also be selected.