By Patrick McLaughlin
One of the articles in this issue makes the case for fiber-optic cabling as the "greener" (i.e. more environmentally friendly) choice for the physical-layer support of enterprise networks. The persuasive argument contains a healthy amount of detail, and the stance is not surprising when you consider the article's co-authors wrote it on behalf of the Telecommunications Industry Association's Fiber Optics Technology Consortium.
One of the points the authors use to illustrate fiber's potential for overall efficiency is the deployment of a passive optical LAN (POL). The article deals with this network architecture in a straightforward technical manner, but I think the handwringing over this technology is only beginning.
I have used the term POL liberally and from what I can now tell, the nomenclature is still being sorted out. What I have called POL, some call optical LAN or OLAN and explain that POL is a subset of OLAN.
Either way, what we're talking about is a cabling architecture that uses singlemode fiber in an enterprise network's horizontal space. It might be oversimplifying a little bit, but not much, to say an OLAN/POL applies the fiber-to-the-home architecture inside an enterprise. OLANs promise (or threaten) to be a disruptive technology that can dramatically change the business and practice of deploying enterprise-network cabling systems. Many of the products that fill telecom rooms and traverse building spaces when the common hierarchical-star architecture is deployed simply are not part of the OLAN architecture.
As for installation practices, OLAN advocates say the process is easier and less expensive than what is called for with traditional setups. And if there's a stigma attached to installing fiber-optic cable, there shouldn't be, they say. All installers who are in your comfort zone installing singlemode fiber, you know what I'm talking about. All who are not, see what I mean about the handwringing?
Proponents scored a public-relations coup when the TIA had a donated POL installed in its new headquarters. Critics of POL point out the architecture is generally inflexible, requires the use of many backup-power devices (striking a blow to the energy-efficiency argument), and is a good fit for some users, but not everyone.
How will this end? Don't ask me. I'm the guy who thought Cat 6 was the last twisted-pair spec we'd ever see. Now if you'll excuse me, I need to go find out all I can about Cat 8 for an article in our next issue. ::
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