Is it difficult to select C ffiberlink switches? Switch selection guide is here!

Cffiberlink  has a very rich distribution and transmission product line, including industrial-grade managed switches for 5G optical fiber communication equipment, intelligent POE, network switches, and SFP optical modules. Among them, the switch product line alone has launched more than 100 models.

There are many models, and it is inevitable that there will be times when you are dazzling.

Today, we will systematically sort out the selection method of switches for you.

01【Choose Gigabit or 100M】

In the network of the video surveillance system, a large amount of continuous video data needs to be transmitted, which requires the switch to have the ability to stably forward data. The more cameras connected to a switch, the greater the amount of data flowing through the switch. We can imagine the code flow as the water flow, and the switches are the water conservancy junctions one by one. Once the flowing water flow exceeds the load, the dam will burst. Similarly, if the amount of data forwarded by the camera under the switch exceeds the forwarding capability of a port, it will also cause the port to discard a large amount of data and cause problems.

For example, a 100M switch forwarding data volume exceeding 100M will cause a large number of packet loss, resulting in the phenomenon of blurred screen and stuck.

So, how many cameras need to be connected to a gigabit switch?

There is a standard, look at the amount of data forwarded by the upstream port of the camera: if the amount of data forwarded by the upstream port is greater than 70M, choose a gigabit port, that is, choose a gigabit switch or a gigabit uplink switch

Here’s a quick calculation and selection method:

Bandwidth value = (sub-stream + main stream) * number of channels * 1.2

①Bandwidth value>70M, use Gigabit

②Bandwidth value < 70M, use 100M

For example, if there is a switch connected to 20 H.264 200W cameras (4+1M), then according to this calculation, the forwarding rate of the uplink port is (4+1)*20*1.2=120M >70M, in this case, a gigabit switch should be used. In some scenarios, only one port of the switch needs to be gigabit, but if the system structure cannot be optimized and the traffic can be balanced, then a gigabit switch or a gigabit uplink switch is required.

Question 1: The calculation process of the code stream is very clear, but why multiply it by 1.2?

Because according to the principle of network communication, the encapsulation of data packets also follows the TCP/IP protocol, and the data part needs to be marked with the header fields of each protocol layer to be transmitted smoothly, so the header will also occupy a certain percentage of overhead.

The camera 4M bit rate, 2M bit rate, etc. we often talk about actually refer to the size of the data part. According to the proportion of data communication, the overhead of the header accounts for about 20%, so the formula needs to be multiplied by 1.2.

So, how many cameras need to be connected to a gigabit switch?

There is a standard, look at the amount of data forwarded by the upstream port of the camera: if the amount of data forwarded by the upstream port is greater than 70M, choose a gigabit port, that is, choose a gigabit switch or a gigabit uplink switch.