A PoE switch is a switch that supports the power supply of a network cable. It can not only realize the data transmission function of ordinary switches but also supply power to network terminals (such as video cameras and AP wireless devices). Simply put, he is a switch that can supply power, so how to configure a PoE switch?
PoE switches are classified into network-managed PoE switches and non-network-managed PoE switches. Non-network-managed PoE switches are specifically designed to meet PoE power supply requirements, plug and play, and require no configuration. The unmanaged PoE switch with mode switch also supports three working modes of standard switching, video surveillance, and VLAN isolation, which can adapt to various complex environments.
Network-managed PoE switches provide multiple network management methods, such as console-based (Console), web-based, and Telnet remote access to the network. First of all, there must be a configuration line for the switch. The original PoE switch connection cable is generally a console cable connected to the switch, and the other is a serial cable connected to the computer. Yes, there is a special reserved management network port.
Therefore, the network administrator can monitor the working status and network running status of the switch in real time, locally or remotely, and manage the working status and working mode of all switching ports globally. The network management switch supports the SNMP protocol. The SNMP protocol is composed of a set of simple network communication specifications. It can complete all basic network management tasks, requires less network resources, and has some security mechanisms. The working mechanism of the SNMP protocol is very simple, mainly through the exchange of network information through a variety of different types of messages, namely PDU (Protocol Data Unit).
There are also network-managed switches that provide policy-based QoS (Quality of Service). A policy is a rule that controls the behavior of a switch. A network administrator uses policies to allocate bandwidth, priorities, and control network access to application flows. The focus is on meeting the bandwidth management policies required by service level agreements and the way in which policies are issued to switches. Multi-function light-emitting diodes (LEDs) at each port of the switch to indicate port status, half-duplex / full-duplex, and 10BaseT / 100BaseT, and switch-level status to indicate system, redundant power supply (RPS), and bandwidth utilization LED forms a comprehensive and convenient visual management system. At present, most of the switches below the department level are mostly unmanaged, and only enterprise-level and a few department-level switches support the network management function.
What is the power supply of PoE? How many devices can be connected, the power is greater than the PoE switch, can you continue to supply power? PoE switches are so expensive, is it safe to buy expensive ones? Your sixth sense is right. In fact, the total power of a PoE switch is a very important indicator, which is directly related to how many cameras can be taken.
To see how many cameras are powered by a PoE switch, consider: the power supply standard of the PoE switch and the actual power of the PoE switch. There are two power supply standards for standard PoE switches on the market, IEEE802.3af and IEEE802.3at. The IEEE802.3af standard defines a power supply of 15.4W, and the IEEE802.3at standard defines a power supply of up to 30W. This is because the power supply standard of a single port is different.
The most common camera power on the market is 7W, and you can use af standard PoE switch. If the camera exceeds 16W, you need to use a standard PoE switch. If the camera power is more than 30W, you need to use a dedicated PoE power supply module.
In simple terms, if a PoE switch is compatible with both af and at power supply standards, its power supply is adaptive.
Let's talk about the total power of the PoE switch.
With the development of power supply technology, at the same time, in the network monitoring, in order to reduce wiring costs and easy and fast use, most engineers will consider using PoE power supply. Taking the PS504E 4-port PoE switch mentioned above as an example, the total power is 60W.
Under the IEEE802.3af standard, it can supply 4 ports (60 / 15.4 = 4), that is, it can power 4 cameras at the same time, that is, full load power. If it is calculated according to IEEE802.3at standard single port maximum power supply 30W, at the same time can only power up to 2 ports (60/30 = 2).
In actual use, the maximum power consumption of many cameras does not exceed 15W. Assuming that each PoE switch port is calculated according to the maximum power (30W), the problem of uneven power distribution may occur. How to solve it?
Don't worry, the current HRUI PoE switches support intelligent power management, which can avoid this situation and make more efficient use of PoE switches for power supply. It is assumed that when the power of the powered device exceeds 60W, this product can preferentially cut off the power supply of the low-level ports to ensure continuous power supply to important ports.
In short, 1. Use a switch that supports dynamic power allocation to maximize the power supply efficiency; 2. Understand the maximum power consumption of the powered device, and then divide the total power supply of the PoE switch by the maximum power consumption to get one How many devices a PoE switch can power.