Steve Smith
In both the premises and campus environment, media converters are letting designers, installers, and network managers avoid the expense of deploying expensive networking hardware to connect one type of cabling media to another. Whether it's copper to fiber or singlemode fiber to multimode, a variety of media converters are emerging that can increase a network's functionality without great expense, while extending the life of existing equipment (see Product Update table, page 134).
Media converters link different cabling media, converting data signals on one to signals that can be carried over the other. "They make it possible to extend the life of legacy networks with the latest technology, rather than having to tear everything out and start over when new technology becomes available-or even worse, being stuck with an old technology," explains Allied Telesyn product-marketing manager Mark Benevento.
In essence, media converters provide the benefit of longer-distance fiber-optic cable networks within the context of an existing copper-based network and offer the option of incorporating high-bandwidth hubs and switches. For a new network, media converters can provide a reverse economy benefit by letting a high-bandwidth fiber backbone feed lower-speed fiber or copper cable to the desktop.
Moving away from Ethernet
With higher-bandwidth demands on the local area network (LAN), network designers and installers are moving away from standard 10-Mbit/sec Ethernet to 100-Mbit/sec Fast Ethernet. On the typical Category
3-based copper line, however, Fast Ethernet dramatically impacts the available transmission distance, rendering the existing cable solution impractical. The choice then be-comes upgrading to a complete Category 5E or pending Category 6 installation-an expensive project with no guarantee that it will be the last upgrade necessary.
While side-by-side price comparisons still favor copper over fiber, many network designers are using media converters to give their customers the best of both worlds-their existing copper infrastructure with the high-bandwidth, security, and heavy-duty benefits of fiber. For many Fast Ethernet conversions, then, the network is typically becoming a mixed media of copper and fiber.
Media converters are considered a means of "futureproofing" a LAN, no matter what lies ahead for copper-cabling standards, and some of this summer's offerings are riding high on that bandwagon. IMC Networks' (Foothill Ranch, CA) iMcV-LIM 10/100 is a dual-speed media converter designed to futureproof a system against changes in cabling bandwidth, distance, and security. It can be configured for Ethernet only or Fast Ethernet only, with seamless upgrades from 10 to 100 Mbits/sec without needing to replace the media-converter module. For installations re-quiring longer distances, a singlemode version can be used on each side of the fiber segment to extend the cabling distance to as much as 30 km.
IMC has also unveiled its iMcV-Gigabit converter that allows migration to Gigabit Ethernet over both copper and fiber systems. IMC says its device will extend the distance of Gigabit Ethernet signals from 100 meters to more than 40 km, without the use of fiber switches and routers, letting companies save money by using copper-based switches and routers while deploying the iMcV-Gigabit only to those ports requiring longer distances.
"It's ideally suited for medium-sized and large companies and campus environments where network backbone systems extend beyond a single computer room," explains Jerry Roby, IMC Networks president and CEO.
Both the iMcV-LIM 10/100 and iMcV-Gigabit converters feature the company's proprietary FiberAlert fault isolation circuitry that will detect breaks in the link.
Allied Telesyn's (Bothell, WA) AT-MC1001 series of Gigabit Ethernet media converters lets network designers and managers extend the size of their network by converting 1000Base-
SX ports to 1000Base-LX. The company says this technology can increase the maximum fiber cable distance from 200 meters to 70 km.
The AT-MC1001 series is part of 11 new media-conversion products introduced by Allied Telesyn this summer. Each is designed to facilitate long-distance network segments via singlemode fiber, converting from copper or multimode fiber network segments. "Multicampus networks are common today, and more and more network managers are looking for efficient and inexpensive ways to link them," says Vince Ricco, senior vice president of sales. "Fiber continues to make sense-for the data security, bandwidth, and distance advantages it provides."
Also touting futureproofing is Transition Networks Inc. (Minneapolis) with its Conversion Center PS-a high-density, multiprotocol, multimedia converter mounting option that can be used with the company's suite of copper to fiber media converters. Designed to grow with the needs of the network, the Conversion Center PS provides a single management source for up to 135 conversion points. Programmable onboard memory allows for future upgrades in the field.
Management a critical feature
Like Transition Networks, Lancast Inc. (Nashua, NH), a pioneer in media-converter development, sees management as a critical feature of next-generation converters. Software that lets network managers remotely troubleshoot and configure converters in an enterprise system can help keep the network running smoothly and minimize information-technology staff costs. Lancast says its software-management solution overcomes the "unwelcome management black hole" at each fiber/copper interface, where determining whether a media converter was functioning properly would otherwise require going to multiple wiring closets that could be located miles apart.
Lancast's Intelligent Media Converter 7500, installed with NetBeacon management software, gives network managers an instant alert to conditions affecting network performance. The software lets managers adjust operating parameters remotely and switch hardware settings across the network without having to take numerous trips to numerous wiring closets. The 7500 is available in 120/240-V AC power for enterprise networks and 48-V DC for telecommunications applications. Lancast's new 7500 MicroChassis model is designed for applications requiring a single line of managed fiber-optic connectivity at a remote site.
Similarly, Allied Telesyn's newest breed of media converters includes management tools such as a fiber link test switch that lets managers conduct on-the-spot checks of fiber connection between two media converters in back-to-back applications, and the company's MissingLink that informs the hosts to perform corrective action if a link fails.
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