Is Gigabit Ethernet over Copper Picking Up Speed?

By Lynn Haber | Oct 11, 2001 | Print this Page
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With the lions share of the market running some iteration of Ethernet, the prospects for adoption of the most recently approved Ethernet standard, or IEEE 802.3ab, for Gigabit Ethernet over copper cabling, looked promising. However, the numbers never stacked up the way industry pundits predicted. With no reversal in the corporate need for network speed, why arent businesses biting?

The truth of the matter is that businesses are very keen on Gigabit Ethernet over copper. The problem for the slow uptake of Gigabit Ethernet over copper products has more to do with slower than expected product shipments than lack of market enthusiasm, according to industry watchers.

Despite the fact that the IEEE approved 802.3ab in June 1999, all the bugs in the silicon werent worked out in 1999, which meant that significant system sales didnt begin until late 2Q of 2000. Furthermore, significant purchasing volumes only became evident in Q3 2000, says Lauri Vickers, senior analyst at Cahners In-Stat Group. "As a result, prices havent dropped," she adds.

Initial market research reports from Cahners forecasted worldwide revenue of one billion dollars for the Gigabit Ethernet over copper product market for the year 2000, and port shipments of over one billion units. Later, readjusted forecasts from Cahners lowered revenue expectations at $70 million and 110,000-115,000 ports shipped for the same year.

Pricing per port for copper-based Gigabit Ethernet products are about one-third lower than for fiber, which is around $1,000 per port. Copper-based 1000Based-T ports are currently about $700 and, by year-end, prices are expected to drop to $500 per port. However, 3Com Corp., Santa Clara, Calif., rolled out a $300 per port solution for Gigabit Ethernet over copper which competitors have yet to match. Even at $300 per port, the cost for 1000Base-T is still about three times the price of Fast Ethernet ports, or $100 per port.

"Were pushing the price envelope on server NICs to unleash a wave of [Gigabit Ethernet over copper] adoption," says Paula Daley, director of marketing at 3Com.

The cost/performance proposition for Gigabit Ethernet over copper makes sense for businesses of all sizes. For larger enterprises with fiber cabling, the industry has already seen migration to Gigabit Ethernet. The copper-based standard is expected to spur additional momentum in those network locations where Category 5, 5e or 6 cabling prevails, for example, at the server, server farms or to the wiring closet that is located on each floor within a building.

According to Daley, the continuing deployment of 10/100Mbps Ethernet at the edge of the network is driving the demand for Gigabit Ethernet at the core, or aggregation point, of the LAN. Additionally, she notes, as e-commerce applications require faster and more reliable response times, theres a growing demand for Gigabit Ethernet as a server connection technology.

For smaller organizations, 1000Base-T over copper will enable many firms to upgrade the network backbone without having to install fiber cable. "Its an easy backbone upgrade for these organizations," says Vickers.

Industry vendors also expect to see Gigabit Ethernet over copper implementations at the server farm where bandwidth requirements can easily outstrip Fast Ethernet, or 100Mbps Ethernet, implementations, creating network bottlenecks. While many companies may have wanted to increase bandwidth at the server farms for some time now, the high costs associated with migrating to fiber put Gigabit speeds out of reach. Even with the possibility of doubling or tripling the performance of the servers, network managers who know that they cant fill up a Gigabit Ethernet pipe cant justify the fiber prices while wasting 60%-70% of the bandwidth.

An Ethernet upgrade project, currently underway at the Cambridge, Mass.-based Massachusetts Institute of Technology (MIT), exemplifies how Gigabit Ethernet over copper fits the bill. Using a switching solution from Enterasys Networks Inc. (formerly Cabletron Systems Inc.), MIT is currently in the process of rolling out Gigabit Ethernet over copper in the tele/datacom closets. The university has about 100 buildings across its campus serving more than 900 faculty and nearly 10,000 undergraduate and graduate students.

"Our intention for this year is to deploy 100-200 units," says Tom Coppeto, network manager at MIT.

According to Coppeto, theres about one wiring closet per floor with each closet requiring between 1-20 Gigabit switches, depending upon the number of ports in use. The way the network is configured in the buildings is that on each floor, the downstream ports go to the offices, classrooms, laboratories or wireless access points. Upstream, the Gigabit Ethernet switches link to the backbone network of the building that runs at Gigabit speeds, as well.

On the backbone, MIT uses Cisco Catalyst 4000 10/100 and Gigabit switches, some of which run over fiber, others that run over copper. If the distance between the wiring closet and the backbone is greater than 100 meters the cable of choice is optical fiber. For distances of less than 100 meters than copper cable is used, says Coppeto.

All in all, about 1,000 Gigabit Ethernet switches will be required to serve all the network connections to the end users. The roll-out plan is to deploy several hundred units per year.

Considerations
Despite the slow start for the copper-based 1000Base-T market, industry watchers expect widespread adoption. However, Gigabit Ethernet over copper is not suitable for all applications and companies are advised to consider the cabling infrastructure.

For example, vendors suggest that if a company is currently running Category 3 cabling, the next likely, and most cost-effective, upgrade, will be fiber. For this type of upgrade, fiber providers long-term investment and performance protection.

Category 5, 5e and 6 cabling can accommodate Gigabit Ethernet, says Bruce Tolley, manager of emerging technologies at Cisco Systems Inc., but, he adds, companies should test their Category 5 cable, in particular, before doing an upgrade. "Organizations should test for higher data rates on the pairs and data running on all pairs," he says.

In particular, Tolley notes, companies should test for far-end crosstalk and return loss. Far-end crosstalk defines noise on a wire pair at the far end from the transmitter, that is, the receiver. Return loss defines the amount of signal energy that is reflected back towards the transmitter due to impedance mismatches in the link, such as those caused by connectors.

According to Intel Corp., the 1000-Base T physical layer standard provides 1Gbps Ethernet signal transmission over four pairs of Cat-5 Unshielded Twisted Pair (UTP) cable. The standard covers cabling distances of up to 100 meters, or networks with a diameter of 200 meters. The 100-meter cabling distance is the safe limit for reliable transmission, and the diameter assumes 100 meters in two directions from a switch.

Companies may want to consider fiber, as opposed to copper, for applications in excess of 100 meters, or in situations where electromagnetic interference might be an issue.

"Given the current fiscal environment, if the copper cabling works, it makes sense for businesses to leverage their existing investments," says Tolley.

MIT has multiple types of copper wiring installed including Category 5, 5e and 6. "For Gigabit Ethernet we use a minimum of Category 5e or 6," says Coppeto. All cabling, he says, is tested upon installation to ensure that it can handle Gigabit speeds for future upgrades.

"What we hope to achieve with the Gigabit Ethernet upgrade is increased performance and that all the existing Ethernet equipment will continue to work the way it always hasno surprises," says Coppeto.

Lynn Haber writes on business and information technology from Norwell, MA.