Protecting Power over Ethernet

With lightning protection high on the list of most companies` security agendas, new technologies - such as Power over Ethernet (PoE) present new challenges to those whose brief it is to ensure 100% uptime.

Graham Duxbury, CEO of Duxbury Networking, looks at PoE from a power protection perspective.

All local area network (LAN) cabling and infrastructure designers in Africa, particularly those whose brief it is to prepare blueprints for organisations located in the Highveld region of SA, are aware of the dangers of lightning strikes when it comes to power protection.

But there are many other dangers that characterise the power delivery services throughout Africa. These include frequent power surges and spikes, low voltage "drops" or brownouts and sudden power failures, all of which can spell disaster for sensitive computer equipment.

Ruggedised power protection systems have become de rigueur in Africa as a result.

For companies with mission-critical systems and networks, minimising the consequences of power failures - particularly downtime costs - is a top priority.

The advent of Power over Ethernet (PoE) technologies has highlighted this issue.

PoE devices do not draw electricity from conventional power sources, but directly from the enterprise architecture itself. And it is delivered not via traditional power cables, but over the Ethernet networking cabling itself.

The range of devices that operate in such a way is growing exponentially and include voice over Internet Protocol (VOIP) telephones, wireless LAN access points, security cameras and other appliances.

PoE`s popularity has resulted from it being one of the best means of increasing the efficiency of communications across the enterprise-wide network, without the need to the change the existing cabling infrastructure.

PoE was discovered in 1999 by engineers keen to improve and reduce the cost of the distribution of power to the growing numbers of network devices that were becoming common to most LANs at this time.

A key requirement was the need to ensure interoperability among these devices - so the establishment of a standard was imperative before PoE could be widely adopted.

The 802.3af standard for PoE was recently ratified by the Institute of Electrical and Electronics Engineers (IEEE).

This has highlighted an important achievement for PoE supporters: The ubiquitous Ethernet RJ-45 plug and outlet are the first universally accepted, worldwide power connectors.

No other industry has managed to standardise power delivery across countries and continents to this extent - if at all.

From a technical perspective, PoE extends the already broad functionality of Ethernet by supplying reliable low-voltage DC power over the same Category 5/5e twisted-pair cable that currently carries Ethernet data.

Because of its low power (48 volts) and inherent simplicity - and because PoE devices are not linked to an AC (110 or 220 volts) outlet - the technology will have wide ranging advantages from a power protection point of view.

Firstly, because they are Simple Network Management Protocol (SNMP) manageable, PoE devices can be remotely controlled, enabling cameras and other devices to monitor, manage and even troubleshoot a variety of other devices associated with mission-critical systems.

This means that PoE devices can monitor other PoE devices and report on power delivery (and many other problems) as they occur.

Secondly, power protection is easier because the protection strategy can address the two basic components in a PoE network individually.

These are the Power Sourcing Equipment (PSE) - equipment that supplies power - and the Powered Devices (PD); those that receive and use the power.

Within any given LAN infrastructure, there are far fewer PSEs than there are power points serving a conventional LAN.

Each PSE is able to be the focus of a multifaceted power protection strategy including Uninterruptible Power Supply (UPS) systems and generator backup. This will take care of power fluctuations and disruptions to the PSE.

PD devices will, as a result, be protected not only from power fluctuations, but from damage due to catastrophic power failure resulting from a direct lightening strike to the main power supply.

Moreover, the reserve or backup battery technology needed to store and supply 48 volts is far simpler than that needed to store and deliver 110/220 volts - and significantly safer as well.

Finally, DC power, converted from AC power storage, will be cheaper and will be available for far longer periods - from a comparable storage device. It will also be more stable and reliable.

At present PoE is not designed to power desktop computers, servers or printers. However, this is in the pipeline for the future, along with a host of new devices that are sure to increase the role of IT in providing cost-effective services.

With power protection strategies becoming more robust and all-embracing for PoE architectures, there will be a number of "winners" particularly when viewed against the backdrop of the cost saving and other benefits associated PoE.