What is PoE? What does it have to do with switches?

Power over Ethernet (PoE) answers the problem of reducing infrastructure costs. PoE allows you to power certain devices such as an enterprise grade wireless access point, removing the need for an independent power supply. This reduces the complexity of installing in awkward locations. It is simpler and easier to run one cable than two. 

That is the rationale behind PoE. It reduces the amount of equipment and cables needed to power user devices and saves costs.

Imagine you are a business spanning multiple floors and rooms. You need to install wireless access points as well as surveillance to provide a mobility experience and security to your employees. You could use an electrician to run electrical wiring outlooks in convenient places close to where your devices are going to be mounted and run trunking down the walls. But this will incur unnecessary costs.  Or, you could use PoE to power the wireless access points and surveillance cameras, all from single network cables.

How does PoE work?

Power-over-Ethernet, as it suggests provides electrical power over Ethernet, using the same cable that provides the network traffic.  The most efficient way to offer PoE across the network is to use PoE switches.  You have likely come across a PoE adaptor which can also be used where the existing infrastructure doesn’t have the power budget (We will talk about this later). Using a power point is the best option, but let’s stay focused on PoE switches, as we want to offer the most relevant advice.

Not all PoE are equal

There are several standards for PoE from IEEE determining the kinds of devices they can support. The below table shows the PoE standards relative to reach the full power requirements of the counterpart Wi-Fi standard.

Standard Power at Switch Wi-Fi Standard
802.3af - PoE 15W 802.11a/n
802.3at – PoE+ 30W 802.11ac
802.3bt – PoE++ 60W (4-pair) 802.11ax
802.3bt - PoH 90W (4-pair) 802.11ax

Most switches sold today use the PoE+ standard (802.3at) providing 30 Watts per port. This was plenty for access points installed for the last few years.  However, with the latest release from Ruckus (their flagship R730 access point) , which uses the 802.11ax standard, you need to consider that 802.11ax is officially here and will likely be the standard used for your next infrastructure roll-out. That means you will need switches that support PoE++ or PoH (Power over HDBaseT). Of course, the Ruckus ICX 7150 series and higher provide PoH. The series gives you all the benefits of operating in the Ruckus ecosystem of easy management within their SmartZone controller, both switches and access points.

How much Power-over-Ethernet do I need?

We have lightly touched on this above, but it really comes down to what devices you are planning on connecting. The current 802.11ac standard, which is widely adopted by devices in the market, can in order to gain peak performance from them, require more than 30 watts. So it is important to look for switches with PoE++ or PoH.

Devices are generally flexible with power, meaning they still may work with reduced features or radios on less than 30 Watts, but you are not getting the best from the access point.

If you are planning on installing high-end video displays, surveillance cameras with pan-tilt-zoom functionality and the latest wireless technology using 802.11ax standard, then there is no doubt that you will need to use PoH switches. ICX switches from Ruckus provide 90 Watts PoH power!

PoE Adaptor/Injector

If your network switches don’t support PoE, and you do not have the rationale to upgrade the switches, there is still the option of using a PoE injector/adaptor.

PoE adaptors sit between your switch and the device that you need to connect it to (typically closer to the device than the switch). The adaptors require their own power source, but allow data to pass through them, whilst removing the need for a dedicated power cable to the device.

Need more advice?

Hopefully, you are now convinced that PoE is the best option for your network?  Our experts can help you to find the best solution around your requirements and to ensure that you get the most suited switch and wireless devices for your business needs.