Ten reasons fiber is becoming more cost-effective in horizontal applications

Perceived costs have been a significant hindrance to fiber-to-the-desk. But over the next two years, this hurdle will be lowered.

How soon will fiber make a significant move into the horizontal? Until recently, perceived costs have been the primary factor limiting fiber to building backbones. Over the next two years, however, 10 factors will converge that favor the growth of fiber-to-the-desk (FTTD) by helping to reduce costs. Individually, none of these 10 factors is sufficient to enable significant growth in FTTD. But collectively, they create a powerful force favoring increases in the use of fiber in the horizontal.

These 10 factors are: Gigabit Ethernet, vertical-cavity surface-emitting lasers (VCSELs), 100Base-SX, small-form-factor (SFF) connectors, quick-cure adhesives, mechanical connectors, centralized cabling, reduced cost of ferrules, reduced cable costs, and preterminated cables.

  • Gigabit Ethernet (GbE) reduces the cost of high-bit-rate transmission to the desk by enabling higher speeds in the backbone. As mentioned in last month's column, higher speeds in the backbone directly affect the horizontal. While GbE is not yet common in the horizontal, the cost of a GbE network interface card ($500) is less than half the cost (and 10 times faster) than a Fiber Distributed Data Interface DAS ($2000 to $2400). Because GbE is based on the ubiquitous Ethernet protocol, it enables piecemeal upgrades of a network without requiring wholesale redesign and replacement of existing components. Ultimately, use of GbE should enable auto-negotiation from 10-Mbit/sec to 1-Gbit/sec Ethernet through switches.

  • VCSELs extend the capacity of existing multimode cable plants to the GbE rate and beyond. The low cost of VCSELs also enables wider use of GbE. The use of VSCELs has had two major impacts on the industry. First, it has increased awareness of the importance of the structure of the multimode fiber core, namely that some multimode fibers contain a dip in the refractive-index profile at the core's center. Second, it has prompted transmission-distance guarantees from fiber and cable manufacturers. By providing performance guarantees that exceed the distances specified in the GbE standard, end users can feel comfortable that their installed cable plant will support future protocols, operating at even higher data rates. These extended distances also will enable increased link lengths in future collapsed backbone networks.

  • The proposed 100Base-SX standard (SP-4360) Fast Ethernet at 850 nm is expected to be ratified early in 2000. At this point, there are no significant technical barriers to completing the standard, and a host of products compatible with the draft standard are being released. This low-cost, fi ber-based Fast Ethernet standard uses light-emitting-di ode technology to a chieve Fast Ethernet, providing network managers a cost-effective migration path from 10 to 100 Mbits/sec instead of the "forklift" upgrade of the entire network that was required when changing to 1300-nm electronics. In addition, 100Base-SX enables reduced-cost, collapsed FTTD backbone networks. One can expect 10/100 network interface cards with auto-negotiation to be available in the price range of $120 to $160. This price represents a reduction of approximately 50% from the current cost of 1300 nm.

  • SFF connectors represent another significant factor that can reduce the cost of FTTD. Designed to cost less than traditional fiber connectors, SFF connectors have a footprint similar in size to the copper RJ-45-style eight-pin modular jack connectors. Because of their small size, SFF connectors can increase density and therefore reduce the cost of hubs and switches, lower patch-panel and enclosure costs, reduce jumper costs, and reduce connector installation costs. Six different SFF connector designs currently are available.

  • Quick-cure adhesives were introduced in 1992. These products, which include anaerobic adhesives, eliminate the need for heat curing and long cure times and enable higher installation rates (12 to 15 per hour and above). These adhesives offer several advantages for the FTTD environment and have been proven to withstand environmental changes.

  • Mechanical connectors are the fastest connectors to install. Their ease-of-installation and the ability to eliminate polishing time can help lower a system's total installed cost in high-labor-cost environments. While the prices for these products tend to be higher than traditional epoxy-based connectors, the learning curve for installation is often faster than for more-traditional products and enables contractors to quickly expand their trained technician team.

  • Centralized cabling (TSB-72) lets network designers take advantage of the high bandwidth and low attenuation of multimode fiber to centralize local-area-network electronics in one communications room within a building. The fiber network interface card connects directly to a router, switch, or hub in a central distribution facility in the building. Centralized networking using optical fiber offers users the ability to contain--and even reduce--their operating costs, while simultaneously adding flexibility, control, and accessibility to their networks. The use of this topology completely eliminates one level of electronics in the network. In addition, centralized cabling reduces the real cost per port by increasing the port utilization. Finally, this topology reduces network cost through elimination of all the expense associated with power conditioning and environmental controls in the wiring closet.

  • Lower ferrule costs are also on the horizon. The cost of ST-compatible connectors with ceramic ferrules is falling, with a single piece price down to $1.60. Use of liquid-polymer ferrules, which are molded and not machined or formed, also reduces the cost of connectors.

  • Reduced cable costs are at hand, as well. As fiber continues to penetrate the horizontal, increased competition for fiber-optic cables in the premises and campus marketplace ultimately will serve to reduce cable prices. As a result, we expect significant competition in fiber-optic cables in the premises and campus marketplace. This competition can only result in a reduction in cable prices.

  • Preterminated cables have enjoyed a growing acceptance since 1994. Such cables can reduce the need for field installation of connectors and reduce installation cost.

What is impressive about this list is not, as stated earlier, one specific element, but rather that so many advances are being made simultaneously that support the use of fiber over copper. The greatest limiting factor is how quickly network planners can learn about and understand these important developments. For MIS managers faced with the challenge of installing robust, reliable, and cost-effective cabling infrastructure, these areas deserve their attention.

Eric R. Pearson, certified professional consultant, is president of Pearson Technologies Inc., a fiber-optic consultancy and training corporation. Elizabeth Goldsmith writes on behalf of the TIA Fiber Optics LAN Section. Member companies include: 3M, AMP, Allied Telesyn, Berk-Tek, Belden Wire & Cable, CommScope, Corning, LANCAST, Lucent Technologies, MicroLinear, Ortronics, Panduit, Siecor, Siemon Co., SpecTran, Sumitomo Electric Lightwave, and Transition Networks. For more information from the FOLS, please visit www.fols.org.

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