How to choose a PoE switch?

Hello everyone,

This blog describes PoE switches in detail and will give you an overview of how to choose a PoE switch.

Power Supply Standards

The power supply standards for PoE switches are classified as PoE (IEEE 802.3af), PoE+ (IEEE 802.3at) and PoE++ (IEEE 802.3bt). Here list some PoE switch for example:  S5720-12TP-PWR-LI-AC, S5720-28TP-PWR-LI-AC, S5720-28X-PWH-LI-AC. Generally, if the switch is named with PWR or PWH inside it means that PoE power can be used. Before purchasing a switch, you need to determine what power supply protocols are supported by the PD device. The power supply protocol supported by the switch needs to be consistent with the PD device. Also, PoE switches can be divided into standard PoE switches and non-standard PoE switches. Non-standard PoE switches have security risks, such as burning out the network devices connected to them. When using a non-standard PoE switch, its power supply voltage and the voltage of the powered device must be the same. The standard PoE switch can automatically connect to the network devices connected to it, and only network devices that support the PoE power supply PoE switch will start to supply power to protect the safety of the powered devices. The biggest difference between non-standard POE switch and a standard POE switch is that: standard POE switch is an intelligent power supply, non-standard POE switch is vice versa, so it is easy to burn in the situation.

Power

In addition to choosing a standard PoE switch, you need to pay attention to the power required by PD devices. Here are some PoE power for fuether understanding: PAC-500WA-BE, LS5W2PSA0870, PDC-650WA-BE. IEEE 802.3af standard PoE switch single port output power is 15.4W, IEEE 802.3at standard PoE switch single port output power is 30W, IEEE 802.3bt (Type 3 PSE) standard PoE switch single port output power is 60W, IEEE 802.3bt (Type 4 PSE) standard PoE switch single port output power is 90W. So you need to choose the switch with the corresponding power according to the PD device, and it is recommended to choose the switch with slightly higher output power than the power required by the PD device.

Number of PD devices

Usually, one port of the PoE switch is connected to one PD device. So the number of PD devices needs to be considered when choosing a PoE switch. For example, in a small home network with only a few PD devices, choosing a 4- or 8-port PoE switch is sufficient, but in an enterprise or campus network with a large number of PD devices to be connected, a 48-port PoE switch needs to be selected. The maximum number of ports supported by Huawei PoE switches can reach 48 ports. For subsequent expansion needs, the ports of the PoE switch should be larger than the number of PD devices.

Transmission rate

The highest rate that the port needs to support needs to be considered based on the PD terminal and business requirements. Taking network monitoring as an example, if the monitoring device is configured with HD cameras, but the bandwidth is not sufficient to support HD propagation, packet loss will occur and affect the monitoring effect (delay, lag). To achieve a smooth HD effect, a high-speed rate PoE switch can be used. Huawei PoE switches support 10BASE-T, 100BASE-TX, 1000BASE-T, and 2.5GE BASE-T interfaces, which provide 10M, 100M, 1000M, and 2.5G transmission rates, respectively.

Power supply distance

Whether PoE, PoE+ or PoE++, the theoretical power supply distance is 100 m. If you need a longer power supply distance, you need to consider PoE network extenders. Some of Huawei’s PoE switches (S5720-28X-PWH-LI-AC, S6720-32C-PWH-SI-AC, and S6720-32C-PWH-SI) can supply power up to 200m when docked with specified models of Huawei APs under the specific port and network cable requirements.

Other

PoE switches usually use network cables to power and transmit data to PD devices, so the quality of the cable is also closely related to the transmission distance and transmission rate of PoE switches.

Hope this can help you with how to choose the PoE switch.