PoE: more than just remote powering

Scott Penno, Australia Country Manager, Allied Telesis, looks at how power over ethernet (PoE) can benefit SMEs and argues that it’s about far more than pushing power through LAN cables.

The ethernet has been connecting PCs, servers, switches and printers for more than four decades. In the space of 40 years, it has undergone a remarkable series of evolutions that have enabled it to deliver so much more - opening the way for applications such as keyless entry systems, videoconferencing, IP security cameras and voice over IP (VoIP) to mention but a few.

The network is now busier than ever and while the organisations are maximising all available bandwidth, they are not necessarily maximising power efficiency. Not many businesses recognise that PoE is capable of far more than simply feeding power down a cable. It offers a range of advantages including cost and power savings, business continuity, improved control and better system backup.

Cost savings

One of the main benefits of PoE is the cost savings. Using ethernet to deliver power reduces the time and cost of installing separate cabling, AC (alternating current) outlets and wall sockets. Plus it eliminates the need for a dedicated UPS for individual devices connected to the ethernet.

Green credentials

Whether motivated by environmental concerns or rising energy costs, most business users have good intentions to ‘go green’ and reduce power consumption. We’ve made some headway, as evidenced by the increasing number of people who turn the lights off as they leave their office in the evening. Yet the vast majority of people don’t think twice about leaving phone chargers or laptop power adaptors plugged in, even when the device is not using the power source.

How many offices can switch off networking or networked equipment like wireless access points, IP phones or surveillance cameras? Probably one in a million. This is where PoE comes into picture. PoE-powered devices can be powered on or off remotely, giving far greater control while maintaining the level of high security that devices like surveillance cameras need. Powering off selected devices ensures you only pay for power that you’re actually using.

PoE can provide power to VoIP phones for emergency use and enables a business owner to power down phones at selected times simply by using software controls, saving the business energy and money.

Take, for example, a company with 200 employees using VoIP phone systems across the business. Each phone handset consumes between 2 and 7 W of power each day when not in use. If the business uses PoE to power down equipment for 12 hours overnight, on weekends and during personal and public holidays, it could save as much as 8736 kWh over the course of a year. In the process, it would reduce the company’s annual power bills by more than $2500.

Access to difficult locations

PoE-powered devices require less cabling compared to AC-powered devices. They are, therefore, easier to install and replace, and more convenient to use. What’s more, fewer cables results in a cleaner look. With a PoE adaptor there’s no need for an AC outlet at the location of the endpoint.

PoE also provides easier access to hard-to-reach locations or where there is a lack of space for power deployment, such as external walls or interior ceilings. In locations such as this, a business won’t have AC power, but may have devices that require power. PoE eliminates the need for high-voltage cabling.

Maintaining an uninterruptible power supply (UPS)

Nobody wants to run the risk of losing business data, which is why most businesses carefully protect their access to traditional power through the deployment of uninterruptible power supply (UPS) devices. What is not so widely realised is that with PoE, businesses can use UPSs to protect much more than a server.

Consider an IP phone system. In the event of a power cut, all IP phones plugged into a wall outlet will lose power. If the endpoints are powered through a central PoE switch, however, and if the PoE is plugged into a UPS, power is maintained and the system is protected.

Control over power and the network

It’s a fact of life that at some stage IT equipment may stop working and enter a state where it cannot listen to NMS commands. This is where PoE boasts significant advantages over AC. When PoE-powered equipment hangs, the IT administrator has greater control and can easily power cycle the equipment.

PoE also enables better control over the network. A small business owner can make power-rationing decisions centrally for all PoE devices by configuring through the switches. In the case of a fully integrated system where PoE is used to power access points and door entry and intercom systems, SMEs can develop a management system intelligent enough to power down PoE devices when the property is empty.

Futureproofing the network

With standards improving all the time, devices are becoming more energy efficient and networks are becoming more powerful. The result? We’re not that far off being able to manage and power the entire IT system from servers to user devices as a single entity. That’s great news for resource-stretched SMEs or for organisations where people regularly leave their power supplies plugged in, draining power even when their laptop battery is fully charged.

PoE will continue to gain momentum as additional compatible devices are developed and new applications emerge.