Design: Law firm replaces UTP with fiber to bring bandwidth to desk

Advances in technology lower the premium for fiber-optic structured cabling to just 16%.

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Advances in technology lower the premium for fiber-optic structured cabling to just 16%.

Dan Silver / 3M Corp.

Conventional wisdom has been that it is too expensive to install fiber to the desk when upgrading a cabling system. So when Parsons Behle & Latimer, one of Utah's leading law firms, prepared to upgrade its twisted-pair copper-cabling infrastructure, systems engineer Kevin Black assumed that copper would be the most cost-effective option.

"As we started this process, I figured we might need to install Category 5 because fiber was too expensive and we would have to recable in five years," Black says. "But when we did a detailed comparison of the installed cost of fiber and copper, fiber was only 16% higher. I had no difficulty convincing management that this relatively small premium was well worth the higher performance and longer life of fiber. The installation has dramatically improved networking performance and prepared us to advance well into the new century without recabling."

Changing the cost equation for horizontal cabling are several factors. These include the availability of small-form-factor (SFF) connectors, which are less expensive and easier to install than traditional connectors; the use of media converters, which allowed the law firm to leverage its existing copper-based network interface cards (NICs) and hubs; and taking advantage of fiber's bandwidth capabilities to install longer cable runs.

Previous twisted-pair installation

Parsons Behle & Latimer, founded in 1882, is one of the oldest and best-known law firms in the intermountain region. The firm employs more than 100 attorneys, who focus on nine major practice areas: litigation, natural resources, environmental, corporate, tax and technology, intellectual property and technology, real estate, banking and finance, and employment. Parsons boasts one of the largest litigation departments in the Intermountain West and one of the largest natural-resources practices in the United States. Its labor and employment law practice is the broadest and most extensive in Utah. The law firm occupies six stories of the Utah One office building in downtown Salt Lake City and has approximately 250 employees.

The law firm installed the previous twisted-pair copper cabling in 1991. The network used a single switch, with each port feeding a 10-Mbit/sec hub that served 40 to 60 people. There were a number of problems with the original cabling installation, such as kinks and cables running over lights. This installation provided acceptable performance at first, but as network traffic increased, problems developed.

Connections were frequently dropped. Performance degraded by a noticeable level during periods of heavy usage. Finally, the telecommunications closets on each floor were hard to reach because they were hidden behind cubicles or bookcases so it took two to three hours to make a move, add, or change. For these reasons, and because management was interested in migrating to more resource-intensive applications that would put an even greater strain on the network, the decision was made to recable the office.

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Parsons Behle & Latimer replaced nine-year-old twisted-copper cabling (left) with state-of-the-art multimode-fiber cable and small-form-factor connectors. Ease of installation and the ability to minimize the number of telecommunications closets required allowed the law firm to simplify the network and improve its performance.

Black enlisted the assistance of a local networking firm, Lumix Communications (Salt Lake City), to provide assistance in evaluating alternatives. "I did a price comparison between Category 5 and Category 6 copper cabling and an end-to-end fiber-based system that used multimode optical fiber, SFF connectors, and media converters," says Kevin Kamerath, senior project manager for Lumix. "I discovered that the price difference between Category 5 and fiber was a lot less than both Kevin [Black] and I expected, while Category 6 cabling was considerably higher. The cost of the fiber cable and connectors was only about 20% higher than Category 5. That's because the new SFF connectors cost less and are easier to terminate than either conventional connectors or copper jacks. This system also eliminates the most expensive part of a traditional fiber installation by using media converters to eliminate the need for new optoelectronics."

End-to-end design

The network design used by the law firm is a complete fiber-optic structured cabling system. Parsons chose to install the Volition Network Solutions from 3M, an end-to-end fiber-optic networking system, although similar products are also available from other suppliers. Significant system innovations included SFF connectors and transceivers as well as new, highly flexible and durable fiber-optic patch cords. Hardware, cable, installation tools, and test equipment complete the passive network from the backbone to the workstation.

The cabling system deployed at the law firm consists of a horizontal cable and backbone cable using 62.5/125- and 50/125-micron Corning InfiniCor high-performance multimode fiber. The cables meet the performance requirements in the Electronic Industries Alliance and Telecommunications Industry Association's specifications for fiber-optic cable. Key to the system is a low-cost, SFF connector designed to have the same size, footprint, and look and feel of the familiar RJ-45-type modular copper-based jack. The simple 2-fiber connector can be installed more easily and quickly than traditional fiber-optic connectors, and the components are significantly less expensive.

The media converter transforms electrical and optical signals, making it possible to build a network that takes advantage of the high-bandwidth, fiber-optic horizontal cabling while using existing copper-based NICs and hubs. The system installed at Parsons includes media converters at each workstation and one at each port in the hub in the telecommunications closet.

"The higher equipment cost for the fiber installation was partially offset by the fact that fiber is capable of longer runs," says Kamerath. "The 62.5-micron core multimode fiber used in this application offers guaranteed performance to 300 meters with Gigabit Ethernet. The alternative 50-micron core fiber goes up to 550 meters. At Parsons, this extra length made it possible to use only one telecommunications closet, instead of one for each floor as in the previous installation. This setup reduced the number of switches that were required. Just as important, eliminating the use of the awkward telecommunications cabinets substantially reduced installation time and has greatly simplified moves, adds, and changes. The new layout involved running two terminations into every office. If a new connection is required, all that has to be done is to plug a patch cord from the termination to the NIC."

"We decided upfront to continue to use 10-Mbit/sec switches driving 10-Mbit/sec hubs for the time being," adds Black. "For this reason, we weren't expecting to see a major difference in performance between fiber and copper in the short run. But the combination of the new fiber cabling and an increase in the number of hubs did eliminate the network drops and performance degradation that had been seen in the past. Another major improvement is that Lumix installed the cable on a much more systematic basis by establishing highways throughout the building and documenting the location of every strand. This makes it easy to find cables if we need to do an add or have a problem."

"While the basic speed on the network hasn't yet been increased," Kamerath adds further, "cleaning up the electrical issues has improved performance by eliminating drops and retransmits that were slowing them down in the past. Plus, they are now ready to move up to whatever speed they want simply by upgrading their electronics."

Faster terminations

Not only is the network capable of operating at faster speeds, but the installation goes faster, too. "SFF connectors are faster and easier to terminate than a Cat 5 jack," Kamerath observes. "I watched the training video, and a few minutes later, I was making good connections. It's so simple that our failure rate was less than 1% when we terminated them. That's as good as copper and much better than typical ST or SC fiber connections."

"This cabling installing," Black says, "has prepared our organization to move ahead for 15 to 20 years without having to worry about the expense and disruption of recabling. Cat 5 cabling would have taken us to the next generation of networking technology, but I have doubts that it would have been able to go any further than that. On the other hand, our all-fiber-based system is already certified for several generations to come and is guaranteed to support every application that will be released in the next 20 years. Chances are that several applications that we install within the next five years will require fiber-optic cabling. For a small cost premium, we have a product that will last four times as long."

Dan Silver is marketing manager at 3M/Volition (Austin, TX) and chair of the Telecommunications Industry Association's Fiber Optics LAN Section (FOLS). He wrote this article on behalf of FOLS. Member companies include 3M/Volition, Allied Telesyn International, AMP Netconnect, Belden Wire & Cable, Berk-Tek, CommScope, Corning, LANCAST, Lucent Technologies, Micro Linear, Ortronics, Panduit, Siecor, Siemon Co., Sumitomo Electric Lightwave, and Transition Networks. To learn more about FOLS, visit its Website at

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