VON conference speakers say PoE needed for VoIP

Sept. 22, 2005
Sept. 22, 2005 - They argue that PoE can eliminate worries about reliability of service.

Power over Ethernet is needed to make Voice over Internet Protocol a quality application.

This was the argument that many presented at this year's VON Fall 2005 Conference & Expo. The gist of their arguments was that, as companies plan to make available Internet Protocol (IP) phones for enterprise end users' desktops, they will need continuous power sources - often Power over Ethernet (PoE) - to make the phones work reliably.

The conference was held at the Boston Convention and Exhibition Center Sept. 19-22. The conference featured representatives from wireline, wireless, and broadband IP communications. The drumbeat of the show was that Voice over Internet Protocol (VoIP) is happening today, and is changing the way the world communicates. But it is facing some definite challenges as end users consider its merit and reliability.

Through VoIP and PoE, enterprises using Power over Ethernet (PoE) can create an integrated data, voice, and powered network. VoIP sends voice over the Category 5e and 6 cables of any IP network, often using a PC as a soft phone. Most networked devices require data connectivity and a power supply. Basic analog telephones, for example, are powered from the central office through the same twisted pair that carries the voice. By using PoE, the same thing is possible for Ethernet services, such as VoIP telephones.

Despite its promises, conference speakers noted that many end users have been reluctant to drop traditional public-switched telecommunications network (PSTN) systems, which are well-established and work reliably. They argue that running voice over a computer network may reduce costs. But can it be counted on to be to provide good quality sound, and uninterrupted service?

If reliability is a concern, then what exactly will it take to make VoIP operate smoothly and efficiently? Again and again in the conference breakout sessions and trade show floor, the answer came down to PoE. PoE is the ability for the LAN switching infrastructure to provide power over a copper Ethernet cable to an endpoint (Powered Device). It opens up the doors for a host of new applications by providing power as well as data connectivity over these existing Ethernet cables.

Kurt Krueger, director of sales for indirect telecom for Ericsson (www.ericsson.com) attended the conference. He noted that IP telephones, like desktop PBX phones, need power for their operation. PoE enables scalable and manageable power delivery and simplifies deployments of IP Telephony, he said.

"We need Power over Ethernet (for VoIP) because we are using Category 5 and 6 cables, and with these applications there is a power issue," said Krueger.

Speakers at the conference argued that by supplying power over the same cable as the data network, these systems can be counted on to deliver the kind of reliability expected from a normal phone system. Viswas Purani, director of emerging technologies and applications for APC (www.apc.com), said PoE eliminates the need for a dedicated uninterrupted power supply (UPS) for individual devices connected to the Ethernet. Poe can centrally back-up IP telephones in the event of a power failure, he said.

"Power over Ethernet is the best way to solve the problems of bringing this (VoIP) to the desktop," said Purani.

This solution comes with its own challenges, however. PoE draws additional electricity, and this means increasing electrical feeds to wiring closets to support PoE. The more phones and switches that are deployed, the higher the heat output.

Purani argued that this calls for better cooling solutions that will keep equipment from overheating. He said end users must consider cooling requirements for wherever a LAN switch might reside - especially in wiring closets.

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