Efficiently Managing Power Consumption of PoE Network Switches

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Today’s ever expanding and high-speed networks need devices that facilitate connecting to dissimilar networks, cover large geographical distances, and increase signal strength and overall efficiency. PoE or Power over Ethernet is one such technology used widely in large networks passing through off-the-grid areas. PoE network switches are power supply devices that transfer power over the same cable transferring data. So, what is network switch power consumption process and what are the ways to reduce the same to save energy. This post discusses the same.

PoE Power Consumption

Network Switch Power Consumption Explained

The energy consumed per unit by a switch is an important factor for a buyer to know. Power used by a switch differs not only based on its type and configuration but also on the IEEE standard for power consumption. This standard is different for PoE, PoE+, and PoE++. This power ranges from 12.95 W to 71.3 W. This depends on the device which receives the power, such as computer, camera, IP phone, and more. It also depends on the number of connected devices to one PoE network switch. Devices such as video conferencing equipment, laptops, and relatively more powerful equipment would require more wattage such as 60 W or 100 W. This table offers information on IEEE standards and their different power levels.


PoE Type

IEEE Standard

Switch (PD) Power

Power per Port

PoE

IEEE 802.3af

12.95 W

15.4 W

PoE+

IEEE 802.3at

25.5 W

30 W

PoE++

IEEE 802.3bt (Type 3)

51 W

60 W

PoE++

IEEE 802.3bt (Type 4)

71.3 W

100 W


With much emphasis on controlling power consumption in any device or system, it is crucial to minimize the Ethernet switches power consumption as well. This helps save cost, power, and increases the efficiency of the network.

Factors That Affect the Power Consumption of PoE Switches

Here are some factors that affect the PoE network switch power consumption.

  • Number of ports: The number of ports in a network switch may range from 2 to 20 and beyond. Out of the total number of ports, only a quarter of them would be PoE enabled for most models. The rest of the ports are usually for RJ45 or SFP ports for Ethernet cable connectors and fiber optics without PoE functionality. The wattage capability is lesser in switches with ports up to 10 than those with ports beyond 20.
  • Number of connected devices: The number and type of connected devices certainly impact the power consumption by a switch. The wattage is distributed over the number of ports. So, if the switch budget is 15.4 W and there are 3 ports, all the ports would not be able to supply the same amount of power over a cable. Also, the requirement of each device would be different. For instance, a camera may require less power than a computer.
  • Type of switch and its wattage: There are hardened industrial switches which are designed for harsh operating environments. Such switches are managed and easily use around 500W power. Unmanaged switches with basic configurations use less power around 50-60W in total for all the ports. So, this largely depends on your application requirement and the type of switch you choose, such as PoE, PoE+, and so on. In most applications, it is wise to choose unmanaged commercial switches with just the right wattage needed.

How to Choose the Right PoE Switch Based on Power Requirements?

Here are some pointers that may help you choose the right PoE switch based on your power requirements.

  • Determine the number of devices that require external power supply and their consumption vis-à-vis your application requirement.
  • Check if the switch is compatible with the concerned devices. This is because some switches may not be able to supply power to certain types of cameras or IP phones which accept power in specific modes.
  • It is important to check the number of connected ports and the amount of energy each PD needs vis-à-vis what each port can supply.
  • Check the IEEE standards for device class and accordingly how much power they will consume. This device class will give you the information regarding maximum power required based on the PoE class or type.
  • Consider the total power consumed by all powered devices in the network. The PoE switch must be able to supply power to all these devices as per their requirement. Also, it uses power for its own functioning which must also be considered. So, if the total requirement is 100W, the switch must be able to deliver the same as well as retain some power for its own functioning. Also, it is important that this happens seamlessly and without any signal losses.
  • It is also important to consider the future scalability when deciding upon the wattage. So, choose a bit larger capacity than what is currently required.

How to Reduce the Power Consumption of PoE Switches?

Saving energy has gained importance over the years, and rightly so. Just like we switch off the lights when we do not need them, turning off PoE switches when not in use helps save energy. Here are some pointers which may help reduce the power consumption of PoE switches.

  • Disabling switches that are not in use is a big step in saving their energy.
  • Use intelligent PoE that auto detects the power each PD consumes so that only the required amount of power is delivered. You can program the settings to automatically turn the switches to standby or sleep mode when not in use.
  • The IEEE 802.3az standard has defined Energy Efficient Ethernet (EEE) to reduce the PoE network switch power consumption by almost 50%, even when it is functioning and connected to all the devices. This is known as Green Ethernet, wherein if a device is not active, the switch detects that link and goes into a standby mode. Also, it identifies the length of the cable and accordingly adjusts the power transmission. The only condition here is that the connected device and the port must be compatible with 802.3az EEE standard.
  • Using green Ethernet also helps identify the difference between a PoE and non-PoE connected device. Hence, the switch would not supply power to a non-PoE device, thus saving energy as well as unnecessary network traffic.

Will PoE Switch Cost More Electricity?

No, in fact PoE switches help save electricity. A PoE switch may seem more expensive than normal switches; however, it is cost effective in the long run owing to the energy saving, reduced network traffic, and overall increased network efficiency. It also saves on taking power from external sources and installing the required infrastructure and wiring for the same. Also, it is easy to manage a PoE switch using SNMP protocol.

It is absolutely essential to save energy and hence use energy-efficient devices in your network. Using energy-efficient PoE switches will help restore available energy as most devices may require less energy than their maximum limit. PoE technology as a whole is a great option for data networks, whether Ethernet, fiber optic, or blended, to save on external energy resources and the concerned infrastructure. However, it is essential to choose the right PoE switch that is compatible in every way for the network. Ensure you source them from reliable and certified suppliers. VERSITRON is a known supplier of a variety of network switches for Ethernet and fiber optic networks. The company offers hardened industrial grade as well as commercial switches with custom options.

Rich Tull

Rich Tull
R.W. Tull is the President of Versitron, a leading technology company specializing in data communication and networking solutions. With expertise in Guiding network switches and media converters, R.W. Tull has played a pivotal role in driving Versitron's success. His deep understanding of these technologies has enabled the company to provide innovative and reliable solutions to clients. As a visionary leader, He ensures that Versitron remains at the forefront of the industry, delivering cutting-edge networking solutions that enhance data communication efficiency.
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