Power over Ethernet -- Ready to Power On? - Page 4
What Is the Catch?
Power over Ethernet equipment has been available for a number of years, so what has changed? The most important change is that a stable, official specification will soon exist that the vendors can build to. Many current products claim to already comply with the forthcoming standard; however, as with any emerging technology, these claims should be taken cautiously, especially for products that have been released significantly in advance of the final version of the standard.
The newly established Power over Ethernet consortium conducted its first round of interoperability testing on a matrix of Powered Devices and Power Sourcing Equipment in April 2003, at the University of New Hampshire InterOperability Laboratory. 3Com, Extreme Networks, Nortel Networks, PowerDsine, and Texas Instruments are members of the consortium. Additional companies that participated in the event included Avaya and Foundry Networks. The results were only made available to the participants.
When considering the purchase of Power over Ethernet equipment, be sure to ask your vendor about interoperability with other vendors' equipment. Even if all your data switches come from a single vendor, the Powered Devices that you and your users want to deploy may come from other manufacturers.
As with Gigabit Ethernet over copper, deploying Power over Ethernet depends on the proper use of Category 5 cable. Some older networks may still have remnants of Category 3 cable or connections in them. Another gotcha to watch for is, on occasion, some installations have economized on cable by "splitting" Cat-5 cable in two, connecting two end-devices with a single cable. Power over Ethernet will not work in such deployments. This is an opportunity to bring your cable infrastructure up to standard.
While the IEEE standard for Power over Ethernet has yet to be completely formalized, a final draft is available for review and the last step in the ratification process is expected in June of this year. The final ratification of the standard will quickly lead to the introduction of many new types and varieties of network appliances. Numerous PoE products have already been announced by all major Enterprise network equipment vendors, making now an ideal time to evaluate the advantages that PoE can bring to your organization. With the capital cost of a pilot deployment running as little as the cost of a few adaptors or a power hub and some powered devices, what are you waiting for?
http://www.iol.unh.edu/consortiums/poe/ - The Power over Ethernet Consortium website
http://www.ietf.org/internet-drafts/draft-ietf-hubmib-power-ethernet-mib-04.txt - Most recent IETF documentation
http://www.ieee802.org/3/af - IEEE Power over Ethernet web pages
Beth Cohen is president of Luth Computer Specialists, Inc., a consulting practice specializing in IT infrastructure for smaller companies. She has been in the trenches supporting company IT infrastructure for over 20 years in a number of different fields including architecture, construction, engineering, software, telecommunications, and research. She is currently consulting, teaching college IT courses, and writing a book about IT for the small enterprise.
Debbie Deutsch is a data networking industry veteran with 25 years experience as a technologist, product manager, and consultant, and has participated in the development of national and international data communications standards. Her expertise spans wired and wireless technologies for Enterprise, Carrier, and DoD markets. She is currently a freelance writer and consultant.