February 28, 2000

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Companies Are Eager For Gigabit Ethernet
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This media could replace fiber connections that move information among network devices in company data centers such as the one at Lawrence Berkeley National Laboratories in Berkeley, Calif. The lab supports 10,000 users and already has an Extreme Networks fiber-optic Gigabit Ethernet switch in-house for network connections. "We rely on a lot of Category 5 cabling to connect our routers and switches, and we expect to move to copper Gigabit Ethernet connections this year," says Matthew Pieklik, a systems engineer at the lab.

The lab's IT group needs higher-speed connections for running the group's research-intensive applications. Cost is also a major issue: The attractive cost of the copper connections would help the agency justify upgrades to links that now may be supporting 100-Mbps Ethernet or 155-Mbps ATM.

The agency has used gigabit over copper connections since the end of last year in a testing environment with beta versions of Extreme Networks' Black Diamond switch and Cisco's Catalyst routers. The links, which operate at distances up to 170 feet, haven't had any problems, Pieklik says.

Another place copper would fit well is with LAN server-to-switch connections, Toysmart. com's Hutchinson says. "Since we operate an online business, a lot of our network traffic moves between our switch and servers," Hutchinson says. "Moving to copper would enable us to drive down the cost of those connections significantly."

Interest in using copper-wire Gigabit Ethernet technology for desktop connections is not as high because only select applications generate enough traffic to fill up a Gigabit Ethernet link. But at the National Institutes of Health in Bethesda, Md., where drug, antibiotic, and treatment research is conducted using homegrown supercomputers, there's plenty of traffic to require the technology for desktop connections.

The NIH has been using Foundry and 3Com Gigabit Ethernet switches to link a couple of dozen researchers to the supercomputers. "We've been paying about $2,000 apiece to connect our users to the network and expect Gigabit Ethernet over copper products to reduce that to well under $1,000," says staff scientist Eric Billings.

Another feature being added to Gigabit Ethernet switches is quality-of-service assurance. Quality of service was designed to support data, voice, and video transmissions on one line. Without it, information travels across Ethernet networks in a random fashion. Packet arrival order isn't important with most data applications because the user will wait as information is sorted. But it's vital with voice and video transmissions--if packets arrive in an improper sequence, a picture may fluctuate or a voice may sound jumbled.

Quality of service also helps users manage bandwidth problems that may occur when applications are in use. On an Ethernet network, bandwidth is parceled out on the fly. So if a user sends a large file when no one else is using the network, the transmission may start out fine--but when a neighbor starts to access a database, the transmission could slow to a crawl. Video and voice apps can't tolerate such fluctuations.

Quality of service solves such problems by opening and maintaining a clear connection between two end points during the entire transmission, so packets arrive in order and crucial applications don't slow down. Yet analysts say it may be some time before the technology finds a wide audience among companies that use Gigabit Ethernet--even some companies running ATM networks are still struggling with the quality-of-service issue.

Part of the problem may be the resources required to manage quality-of-service implementations. To set up such features, a company must create a variety of parameters. For some users, such as the city of Alexandria, Va., it's easier to build a network by assigning permanent chunks of bandwidth to voice and video transmissions.

The city has been installing an ATM backbone network to connect 80 buildings used by a half-dozen agencies. The city decided to go with ATM because it could support WAN connections; the city's network covers a 15-square-mile area and requires 90 miles of cabling.

The city uses the types of applications usually targeted for quality-of-service: voice-over-IP and video transmissions. But, says Gary Post, the city's deputy director of IT, "Quality of service requires that a user enter and manage a great deal of configuration data; we didn't view the benefits as worth the investment."

The city opted not to use quality of service, even though the alternative had its own drawback: Though a permanent virtual circuit assigns bandwidth all the time to certain apps, users may not always fill up the connection, so the company pays for more bandwidth than it needs. Still, the difficulty of ensuring efficiency as apps change or come online by setting up a switched virtual circuit using quality of service would be too great a burden, city officials say.

But as users deploy video and voice-over-IP initiatives more aggressively, they may have no choice but to start using quality of service. It won't happen overnight, though. Says Collins of the Dell'Oro Group, "Because of the cost, acceptance of Gigabit Ethernet over copper will come quickly, but quality of service will experience a slower ramp up."

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Photo by Richard Morgenstein

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