Weak people need to master these POE switch knowledge

POE (Power Over Ethernet) refers to some IP-based terminals (such as IPdian phones, WLAN access points APs, network cameras, etc.) without any changes to the existing Ethernet Cat.5 cabling infrastructure. While transmitting data signals, it can also provide DC power supply technology for such devices. POE technology can ensure the normal operation of existing networks while minimizing costs while ensuring the security of existing structured cabling.

POE is also known as POL (Power over LAN) or Active Ethernet, and is sometimes referred to as Power over Ethernet. This is the simultaneous transmission of data using existing standard Ethernet transmission cables. A new standard specification for electrical power and maintains compatibility with existing Ethernet systems and users. The IEEE 802.3af standard is a new standard based on the Power over Ethernet (PoE) system. It adds the standard for direct power supply through the network cable based on IEEE 802.3. It is an extension of the existing Ethernet standard and the first international standard for power distribution. standard.

PoE switch VS ordinary switch

Ordinary switch: A common Ethernet switch has the function of data transmission and exchange. In actual networking applications, you can simply think of it as a role similar to plugging. Of course, the function is not as simple as plugging.

PoE switch: Unlike a normal switch, a PoE switch has the PoE power supply function in addition to the functions of a common switch. With this feature, PoE switches can power network devices such as webcams, wireless APs, and network dians, eliminating the need for complicated power wiring.

Advantages of PoE switches

1. Advanced technology: Data and power can be transmitted simultaneously using a single network cable, which is more advanced than using multiple lines.

2, convenient wiring: due to convenient wiring, no additional power wiring, in the large and medium-sized monitoring system, can greatly save investment costs.

3. Cost saving: From the engineering point of view, less construction workers, less wire rods and the like can be purchased to reduce labor costs and material costs, and the project construction period can be shortened, and the maintenance difficulty is simplified.

4, high security: because there is no direct strong power supply and strong electrical circuit, improve the safety of use.

How much power can a PoE switch power?

1. AF standard: A PoE switch that complies with the IEEE802.3af standard can supply power to (PD) powered devices with a maximum power consumption of less than 12.95W.

2. AT standard: A PoE switch that complies with the IEEE802.3at standard can supply power to (PD) powered devices with a maximum power consumption of no more than 25W.

3. Under special circumstances: PoE switches support different power supply standards, and the maximum output power supported by the port will be different. For example, the IEEE802.3at standard PoE switch can only supply power to the (PD) powered device with maximum power consumption of less than 25W. However, (PSE) power supply port supports up to 40W power supply equipment, but can supply power to some high power ball machines;

How to choose the right PoE switch?

1. Consider how much power your device is.

Corresponding to how many power PoE switches are selected. If your device's power is below 15W, then you can choose a PoE switch that supports the 802.3af standard. If the power is greater than 15W, select the 802.3at standard high-power switch, or else take it.

2, physical port

First, you need to determine the number of switch interfaces, the number of optical ports, network management, and speed (10/100/1000M). At present, the interfaces on the market are mainly 8, 12, 16, and 24. The fiber port is usually one or two ports, and the optical port must pay attention to whether it is 100 megabytes or gigabit. It depends on the situation.

A PoE switch is generally used to connect to a powered terminal and is used as an access switch. The number of PoE-powered ports supported by the switch is considered according to the number of powered terminals. In addition, you need to consider the upper limit of the rate that the port needs to support according to the receiving terminal and actual requirements. For example, if the port of the AP is Gigabit and 11AC or dual-band is used, you can consider using Gigabit access.

3, power supply parameters

According to the power supply protocol supported by the powered terminal (AP or network camera) (such as 802.3af, 802.3at, or non-standard PoE), the PoE power supply protocol supported by the switch must be the same as that of the powered terminal. Non-standard PoE switches have many security risks. It is recommended that you choose a standard 48V PoE switch device.

4, wiring scheme

The user can compare the cost of the local power take-off wiring with the cost of powering the PoE switch. Currently, PoE switches have a power supply distance of less than 100 meters. No layout restrictions can save about 50% of the overall cost. Within 100 meters of wiring, the network can be flexibly expanded without being restricted by the power line layout. The terminal devices such as wireless APs and web cameras are hung on the walls or ceilings, flexibly expanded, and easily routed and elegant.

5, pre-sale and after-sales technical services

Here to remind the majority of users need to choose reliable brands, choose reliable businesses in order to obtain professional pre-sales and after-sales service. Otherwise, if there is a problem with the PoE switch or you are embarrassed, you are not looking for someone. From this point of view, you still choose the domestic one. Generally, from the above points, you can choose a good PoE switch that you like.

summary

1. Select a switch that supports Dynamic Power Allocation (DPA) (please select a standard PoE switch);

2. First understand the maximum power of the powered device, and then divide the total power of the PoE switch by the maximum power consumption of the (PD) powered device, and you can get how many APs, IP cameras, and IPdians a PoE switch can give. The device is powered.

3. The distance between reliable power supply is up to 100 meters (when the quality of the network cable is good), and the limit of more than 100 meters cannot supply power and transmit data normally.

4. At present, most manufacturers' PoE switches do not have lightning protection performance design, which may cause network paralysis in some areas with frequent thunderstorms.

5. Finally, other precautions should be taken. When purchasing a PoE switch, it is necessary to consider the backplane bandwidth, transmission distance, and specific power supply mode. In addition, try to buy a more professional or well-known brand of PoE switches, do not use forced power PoE or other non-standard PoE products to avoid burning equipment or causing other inconvenience.