Elizabeth Goldsmith
Five years ago, most system planners would not have thought about running fiber to the desktop. It was an option only for those companies where security or reliability--not price--were the main concerns.
That is no longer the case. Although unshielded twisted-pair (UTP) cabling is still a popular medium for horizontal cabling, fiber-optic cable is steadily gaining market share. According to a market survey conducted by the Business Research Group (Newton, MA), fiber`s market share will nearly triple from 7% to an estimated 19% of users from 1994 to 1996. By the end of 1996, almost one in five users will have fiber as their primary desktop environment. The study also shows that 22% of the MIS managers at major U.S. corporations have implemented, or plan to implement, it.
Why are MIS managers seriously considering fiber for horizontal cabling applications? According to the Telecommunications Industry Association`s Fiber Optics LAN Section (FOLS), fiber deployment is driven by increasing bandwidth requirements and the development of architectures that take advantage of fiber`s attributes.
How much bandwidth?
Some say that optical fiber offers too much bandwidth for most premises networks. "To a certain extent, fiber is a hostage of its own success," says Martyn Easton, premises marketing manager at Siecor Corp. (Hickory, NC). "Fiber-optic cable has received so much publicity as a long-distance, high-data-rate carrier that MIS managers don`t believe they need that much capacity or speed."
That perception is changing, however. "End users see their networks bog down as network traffic increases, and they adopt bandwidth-hungry applications such as multimedia and videoconferencing," says Lynda Price, senior product planner, Lucent Technologies Inc. (Morristown, NJ). "They are starting to request improved media, including fiber."
Having enough headroom in your network gives you more than just an upgrade strategy. Installing more bandwidth capacity than you currently need can reduce the risk of system outages. In copper-based networks, outages are caused by electromagnetic interference (EMI), radio-frequency interference (RFI), crosstalk, impedance mismatches and excessive transmission distances. Fiber`s immunity to these factors can increase network reliability by 60% to 80% and reduce system error rates from a few per minute to a few per month, while still providing capacity for growth. "A major benefit for fiber at the workstation," says Price, "is that fiber-optic and electric-power cables can be placed in the same raceway."
Equally important, installing fiber-optic cable can save companies from having to recable systems to support higher data-rate systems. "Historically, MIS managers have accepted the premise that they had to install better grades of copper cable to support upgrades," says Tony Beam, director of fiber systems marketing, AMP Inc. (Harrisburg, PA). "But with data rates nearly doubling every year, they can see the benefits of fiber-optic cabling, which only needs to be installed once."
One difficulty in evaluating fiber and copper in network architectures lies in the fact that most network architectures were originally designed for copper. "Most network planners cut their teeth on copper," says Jon Chester, product manager premises marketing at Corning Inc. (Corning, NY). "They look at fiber as a direct substitute, which may not be the most economical way to use it."
Centralized cabling is, however, changing that mind-set. It provides for direct connections from work areas to the main crossconnect by allowing the use of pull-through cables, or an interconnect or splice in the telecommunications closet, instead of a horizontal crossconnect. This architecture lets the user centralize local area network (LAN) electronics in a building, rather than distributing them to each closet.
Why choose fiber?
Misconceptions about fiber have slowed its use as a mainstream cabling choice. People assumed that fiber was too expensive or too difficult to install. These perceptions changed as the industry started to use the medium in building and campus fiber-optic backbone cabling.
"Price has always been a concern," says Easton. "But, today, the cost of fiber-optic and copper cables is comparable." According to Dan Silver, marketing manager at 3M Telecom Systems Group (Austin, TX), advances in connector technology have also resulted in lower prices. In addition, network planners are beginning to look at the lifetime costs of a network, rather than just the first installed costs. "With a fiber-based network, you have lower maintenance costs, fewer system outages and no need to replace the network`s infrastructure a few years after it has been installed," says Charlie Amann, product manager at Commscope (Claremont, NH).
With training and experience, installers have found that working with fiber is as easy as--if not easier than--installing copper. "Fiber is not fragile," says Chester. "Also, its small size, light weight and tensile strength make it easy to handle, especially when installing in narrow duct spaces." Trish Dawson, director of marketing at Spectran Corp. (Sturbridge, MA), adds that "newer grades of UTP cabling, such as Category 5, are proving more difficult to install and test than previous generations. In comparison, fiber is an established, proven technology."
Lower-cost electronics exist, but are not yet widely available. N. D`Arcy Roche, AMP`s vice president, premises systems and services, says the company`s fiber concentrator and workstation connection devices--network interface cards and transceivers--allow network managers to run LAN protocols such as Ethernet and token ring over fiber-optic cable at total system costs comparable to, or even less than, UTP cable solutions.
"The vendors of active devices need to work with board manufacturers to develop products that will reduce the costs to network interface controller and hub manufacturers," says Silver. "Many users want to move to fiber technology and it`s important that vendors meet those needs."
Early users of optical fiber for horizontal cabling tended to be those with specific needs that only fiber could meet, such as security or immunity from EMI or RFI. "Today, we`re finding that each market area is driven by different needs," says Dawson. "For instance, its immunity from EMI and RFI and fiber`s long link lengths make it ideal for manufacturing."
According to the Business Research Group study, government applications currently represent the largest market for optical fiber, and use will nearly triple by 1996. Healthcare applications are growing the fastest--estimated to grow from 8% to 30% from 1994 to 1996. Fiber use in finance, manufacturing and trade applications also will show healthy increases.
"In the premises market, multimode fiber is following the same path that singlemode fiber took in the telephone and cable-TV markets," says Chester. "As users became educated about its capacity, flexibility, upgradability and reliability, fiber became the standard. Private network users are just now beginning to leverage the same advantages. That`s why the members of FOLS see fiber- optic cabling becoming established for the backbone and riser portions of data-communications networks, and ultimately why fiber will penetrate the horizontal sections as well."