Shedding Light on Dark Fiber

By Peter Coffee  |  Posted 2004-10-18 Print this article Print

Gannett's IT architect reveals how the company is tapping unused fiber to save money and increase bandwidth.

Free and nearly infinite bandwidth sounds like a futurists dream, but its almost the present-day reality of dark fiber—vast numbers of fiber-optic channels in the ground but as yet unlit by lasers and network protocol encoders.

Combined with the plummeting price and improving interoperability of midtier CWDM (Coarse Wavelength Division Multiplexing) hardware, dark fiber is a resource that offers high return on investment to the enterprise IT professional whos willing to explore new ways of buying and managing network capacity.

The supply of fiber-optic bandwidth thats already installed, in a surprising variety of places, vastly exceeds demand at current prices. Industry estimates suggest, for example, that roughly seven-eighths of the city-to-city fiber in the United States and Europe has never been equipped with networking hardware at its endpoints. When supply exceeds demand, prices fall—but only when potential buyers recognize that this situation exists and when sellers accept the need to adjust their expectations.

Gary Gunnerson, IT architect at USA Today publisher Gannett Company Inc. and an eWEEK Corporate Partner, gave eWEEK Labs an inside look at his companys emerging dark-fiber strategy. Gunnersons explorations of emerging network hardware standards and vendor offerings—and his research into more effective ways of matching buyers and sellers of both raw bandwidth and managed services—suggest that momentum is the only missing ingredient for a richer mix of cost-effective communication.

Click here for Gunnersons five-step guide to creating a metro area network. Not only is there a lot of fiber in the ground, said Gunnerson, but the fiber is also becoming steadily cheaper to exploit using CWDM hardware.

CWDM places a relatively small number of channels on a fiber pair—typically four to eight, compared with the tighter spectral packing (that is, more nearly similar colors of light) of DWDM ("D" for dense) technology. DWDM uses 16 to 64 colors per pair.

When fiber pairs are scarce, the tighter tolerances of DWDMs cheek-to-cheek channel packing are cost-effective. However, todays abundance of glass in the ground shifts the balance in favor of endpoint simplicity, especially since few sites exceed the capacity of eight-channel CWDM on a single fiber pair.

CWDM costs are being further pushed down, Gunnerson said, by the late-2003 standardization of CWDM wavelengths. These wavelength agreements give Gunnerson and other buyers greater confidence in the interoperability of CWDM and DWDM hardware on a single cable plant.

That mixed-signal freedom makes CWDM a more attractive entry point for enterprises that envision future growth in their bandwidth needs. It also makes CWDM an option for incremental expansion of established installations.

Next page: Fiber glut.

Peter Coffee is Director of Platform Research at, where he serves as a liaison with the developer community to define the opportunity and clarify developers' technical requirements on the company's evolving Apex Platform. Peter previously spent 18 years with eWEEK (formerly PC Week), the national news magazine of enterprise technology practice, where he reviewed software development tools and methods and wrote regular columns on emerging technologies and professional community issues.Before he began writing full-time in 1989, Peter spent eleven years in technical and management positions at Exxon and The Aerospace Corporation, including management of the latter company's first desktop computing planning team and applied research in applications of artificial intelligence techniques. He holds an engineering degree from MIT and an MBA from Pepperdine University, he has held teaching appointments in computer science, business analytics and information systems management at Pepperdine, UCLA, and Chapman College.

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