How to choose the switch in the project?

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1. The number of ports on the switch

The number of ports of the switch and the number of physical ports supported by the switch determine the number of terminals or secondary receiving devices connected to the switch, which need to be selected according to actual needs. Of course, subsequent network expansion also needs to be considered. The access port of the switch is used to connect to the intranet terminal, and the uplink port is used to connect to the upper-level equipment.
If the number of points is about 16, and the number does not change much in the long term, you can choose a 24-port switch. If the number of points exceeds 16 or more, and there are other network devices, it is necessary to make a certain amount of redundancy for the number of ports at this time. In addition, you can choose a 48-port switch.

2. Port parameters of the switch

Port parameters mainly need to be considered:
Port rate (100M, 1000M, 10000M) and port type (RJ45, SFP/optical port, PoE power supply network port, etc.). There are several optical ports, or several electrical ports, etc., the number of 100M ports and Gigabit ports.

3. The function support of the switch

Consider the functional support of the switch, whether it has network management function, module redundancy, routing redundancy, four-layer switching, scalability, etc. At the same time, the security function of the switch needs to be considered.

Specifically, such as: access control, 802.1X authentication, loopback detection, quadruple binding, IGMP Snooping, etc.

4. The backplane bandwidth of the switch

Backplane bandwidth, also known as switching capacity, is the maximum amount of data that can be handled between the switch interface processor and the data bus, just like the sum of the lanes owned by the overpass. Since the communication between all ports needs to be completed through the backplane, the bandwidth provided by the backplane becomes the bottleneck of concurrent communication between ports.

When we buy a switch, we will see the parameters. The larger the bandwidth, the greater the available bandwidth provided to each port, and the greater the data exchange speed; the smaller the bandwidth, the smaller the available bandwidth provided to each port, and the faster the data exchange speed. slower. That is to say, the backplane bandwidth determines the data processing capability of the switch. The higher the backplane bandwidth, the stronger the data processing capability. If you want to realize the full-duplex non-blocking transmission of the network, you must meet the minimum backplane bandwidth requirements.

5. The packet forwarding rate of the switch

The data in the network is composed of data packets, and the processing of each data packet consumes resources. Forwarding rate (also called throughput) refers to the number of data packets passing per unit time without packet loss. Throughput is like the traffic flow of an overpass, and it is the most important parameter of a Layer 3 switch, which marks the specific performance of the switch. If the throughput is too small, it will become a network bottleneck and have a negative impact on the transmission efficiency of the entire network.

The switch should be able to achieve wire-speed switching, that is, the switching rate reaches the data transmission speed on the transmission line, so as to eliminate the switching bottleneck to the greatest extent. For a Layer 3 core switch, if it is desired to achieve non-blocking network transmission, the rate can be ≤ the nominal Layer 2 packet forwarding rate and the rate can be ≤ the nominal Layer 3 packet forwarding rate, then the switch is doing the second and third layers. Line speed can be achieved when layer switching.

6. The function support of the switch

The switch brand is very important, and different switches are used for different purposes.
In large-scale network projects, Huawei, Ruijie, H3C, Cisco and other brands of enterprise-level switches have high evaluations, each with its own strengths and weaknesses. As domestic brands, Huawei, Ruijie, and H3C are developing rapidly in the field of switches. Cisco, as an established enterprise It has very strong strength and needs to be considered according to the project and its own situation.