PoE power supply refers to the transmission of power while transmitting data to a network device without changing the original network architecture. The carrier is the network cable. PoE is deployed very safely and reliably, and it also saves costs. This is a relatively new network technology, if you can keep in mind the following five tips, you can ensure the successful deployment of PoE.
1. Provide sufficient power to the powered device
This one sounds very easy, but in practice, it is not that simple. The IEEE802.3af standard defines a five-level power supply standard that provides up to 12.95W of power to the powered device. It also needs to consider the power loss caused by the cable length. Therefore, the power supply device must provide no less than 15.4W per port. power. For a 24-port PoE switch, more than 370W of power is required. In addition, the switch needs to consider the power required for the data exchange itself.
Therefore, it is necessary to pay close attention to the power level of the power supply equipment: the PoE power supply module used in the intermediate access method (also in the case of 24 ports) must be no less than 370 W, and the output power of the 24-port PoE switch must be greater than 370 W. As for how much, you need to look at the power consumed by the data exchange of the switch. Generally speaking, a non-PoE switch can be used to measure the power consumed by the switch itself, and with a power of 15.4 W per port, the minimum output power required by a PoE switch can be obtained.
2. Use uninterruptible power supply equipment such as UPS
Some powered devices powered by PoE are often mission-critical devices, such as network dian. Once the power is turned off, the voice is completely cut off and cannot be called. Whether it is the traditional program-controlled exchange dian, or IPdian, it is very important to keep open. Therefore, when designing a network, it is necessary to distinguish such key equipment that cannot stop power supply or stop data transmission, and use a non-stop power supply device such as UPS for backup power supply to keep power and data smooth.
3. Adopt a switch that complies with the PoE power supply standard
When deploying PoE, it is important to ensure that the power and power terminals must be compatible with each other. Of course, if both the powered device and the powered device are PoE compliant, you don't have to worry about it. Once the device on the other end does not claim to be PoE compliant, you need to be cautious.
It is recommended that you carefully read the manual and its technical parameters before using the device. It is not acceptable. You need to contact the manufacturer to ensure that the power supply and the powered device you are using are compatible with each other. If you ignore this one, you will most likely pay the double price of time and money.
4, can not ignore the performance of the cable
Which category are the cables you use? Maybe Cat5, or 5e, or even 6. The higher the cable rating, the smaller the power loss and the better the performance. If there are bad manufacturers, they will be refilled, so it is necessary to carefully read the technical parameters provided by the manufacturer, and whether they really meet the performance of 5e or 6. If you have a good budget, try to use a higher grade cable.
It is also important to remember that only four nodes can exist between a switch or hub to a network card. If the intermediate access method is used and the PoE power supply module is used for power supply, the module itself must also be counted as a node. Many people often ask: What is the longest distance of the cable with PoE power supply? The correct answer is 100 meters from the switch/hub to the network card, not 100 meters from the PoE power supply module to the powered device. The length is not the power supply, but the data transmission.
5, using a more cost-effective PoE deployment method
As mentioned earlier, PoE deployment has two methods, one is the end access method and the other is the intermediate access method. The end access method usually uses a PoE switch as a power supply device. This method is recommended for new networks because the topology is simple and the connection is not prone to errors. Anyway, if you want to buy a new switch, you can spend more money and buy a PoE switch, which is very troublesome.
If you've recently purchased or upgraded a switch, now you're deploying a PoE device and discovering that the switch you just purchased is not PoE, is it a bit frustrating—and you have to re-purchase a new switch that meets the standards. Don't worry, one of the great benefits of PoE is that this technology does not need to uproot the original network, and it can be used from the beginning, it can also use this technology without changing the existing network structure and facilities. convenient.
In this case, it is recommended to use the intermediate access method to connect the PoE power supply module between the original switch and the powered device. This is also 802.3af-compliant. The problem can be solved with a slight increase in cost. .
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