Why you need 90 watts of PoE power

Power-over-Ethernet (PoE) eliminates the need for an additional power source and a second set of cables to each device. The very first Power-over-Ethernet (PoE) standard was ratified by the IEEE in 2003. The nascent standard delivered up to 15 watts of power for devices such as VoIP phones, Wi-Fi access points (APs) and IP cameras. In 2009, the IEEE ratified a new standard for PoE+ that delivered up to 30 watts at the switch. 

Two new standards in one – 60 watts and 90 watts

The unceasing demand for power in the enterprise has only increased over the past decade. As such, PoE is now standard for enterprise networks that support wireless access points (APs), VoIP phones and other devices. However, it should be noted that a new generation of power-hungry APs, video displays, pan-tilt-zoom cameras and many other devices require more than 30 watts. In recent years, individual vendors responded to this demand by creating protocols such as UPoE (60 watts) and PoH (95 watts). These protocols effectively formed the basis of the IEEE’s most recent 802.3bt standard. Ratified in 2018, the new standard defines two levels of PoE power: 60 watts (Type 3) and 90 watts (type 4).

Do I need more than 30 watts of PoE?

Devices that consumed more than 30 watts of PoE were hitting the market even before the 802.3bt standard was officially ratified. The most common devices were new generations of wireless Wi-Fi 5 (802.11ac) and Wi-Fi 6 (802.11ax) access points. Although most of these APs operate at 30 watts, some require more power to drive the 4, 8 or 12 wireless radios to full power – and provide power for devices connected via their USB ports. Put simply, more than 30 watts is needed to take full advantage of certain Wi-Fi 5 and Wi-Fi 6 access points. In many cases, 40-45 watts is enough for optimal AP performance. Additional devices powered by PoE that can benefit from more than 30 watts include HD/4K video displays, point-tilt-zoom cameras, POS systems and smart LED lighting. Of course, this list is only growing.

Isn’t 60 watts more than enough?

As noted above, there are several devices that can take advantage of more than 60 watts of PoE at the switch. Much like Wi-Fi 6 APs operating with only 30 watts, many devices are designed to operate with less than optimal power – but only deliver their full capabilities when maximum power is available. One such example is smart LED lighting. Another is a wide range of IoT devices for office and building automation. We expect this trend to continue in the future for next-generation IoT sensors, access points, and video, as well as AR/VR infrastructure.

If you build it, they will come

The recently ratified IEEE 802.3bt standard is serving as a catalyst for the design of high-powered devices and switches capable of delivering 60-90 watts. Ultimately, we expect the industry to clamor for even higher PoE levels. It should be noted that switch PoE capabilities are an important consideration when purchasing and future-proofing network infrastructure. Currently, the useful life of a switch is typically 5-7 years, although, in some deployment scenarios, the life-span can stretch up to 10 years. This means customers will have to determine how capable their switch purchases are of supporting both current and future PoE requirements.

Buyer Beware

Network vendors have united around the single 802.3bt standard described above. Most vendors advertise their compatibility with this standard, but only deliver the lower power level (60W).  Ruckus Networks (now part of CommScope via acquisition) is one of the few that has implemented the 802.3bt standard to the full 90 watts. While it is often challenging to accurately predict future requirements, having more power available now will significantly increase the odds of being ready for a new generation of energy-hungry devices.

Continued reading:
Getting Wired for Wireless: Power