Gigabit Ethernet switches hit LANs

Gigabit Ethernet switches hit LANs<@VM>The fast lane just keeps getting faster

The Lowdown

  • What is it? A Gigabit Ethernet switch can transfer data at 1 Gbps from the switch to PCs and other equipment. An entry-level Gigabit Ethernet switch typically has between four and eight ports using 1000Base-T copper, 1000Base-SX fiber or 1000Base-LX fiber technologies.



  • When do you need one? You need a Gigabit Ether-net switch for high-bandwidth applications requiring large, fast data transfers among systems on a
    LAN.



  • When don't you need one? You don't need a Gigabit Ethernet switch if your users won't really benefit from faster connections'for instance, if server and disk capacity in a small network can't make full use of the extra speed'and if you can't show a fairly quick return on investment for the switch. You might also already have fast networking that isn't Ethernet.



  • Must-know info? A small, fixed-port Layer 2 switch with either copper or fiber connections is ideal if price and raw throughput speeds are your primary considerations. For greater flexibility, a scalable Layer 3 model with advanced routing capability, VLAN support, advanced traffic management and quality of service support would serve better.

  • D-Link Systems' DGS-3204 provides Layer 2 switching over four 1000Base-SX ports and is priced at $1,295.

    Enterasys Networks' Vertical Horizon VH-8G has eight 1000Base-SX ports for Layer 2 switching. It's priced at $6,995.

    For as little as $250 per port, managers can meet high-bandwidth needs at the local level

    Is there a Gigabit Ethernet LAN in your future? If you go by the numbers, there probably is.

    The worldwide market for Gigabit Ethernet and 10-Gigabit Ethernet products is growing at a compound rate of more than 55 percent annually and will reach more than $24 billion in sales by 2004, according to a report from Cahners In-Stat group, a market research company in Scottsdale, Ariz.

    The Dell'Oro Group, a research firm in Portola Valley, Calif., has predicted that the Gigabit Ethernet market will grow from 1.8 million ports in 1999 to 18 million ports next year.

    The figure is likely to be revised upward in the light of recent developments in copper-based Gigabit Ethernet switching.

    Up to now, Gigabit Ethernet has been used mostly for high-speed wide-area and metropolitan networks.

    But industry analysts expect it to replace 10/100-Mbps Fast Ethernet as the dominant LAN switching technology by 2004.

    Makers of Gigabit Ethernet switches are moving away from an almost exclusive focus on high-end enterprise products to LAN systems. The move will benefit small organizations looking to bring resource-intensive applications such as virtual LANs (VLANs), voice over IP, computer-aided design and manufacturing, and streaming video to their desktop PCs.

    The Gigabit Ethernet switches featured in this guide are designed mainly for LANs; they are scaled-down versions of high-end, expensive enterprise switches.

    They typically have between four and eight 1-Gbps ports, and a few have one or two gigabit-speed 1000Base-T/SX/LX uplink slots.
    Because of the ubiquity of Category 5 copper cable in LANs, many of the newest switches are built exclusively around 1000Base-T copper technology. Other switches use 1000Base-SX or 1000Base-LX fiber, making it easy for them to link up with all-fiber backbone networks.

    Still others, such as Allied Telesyn International Corp.'s Rapier G6 Series and Etherwan Systems Inc.'s Xpresso 3400, offer optional T, SX or LX ports.

    Price is right

    The Gigabit Ethernet LAN switches listed in the chart amount to good deals. A four-port FriendlyNet GX4-400 copper-based switch from Asante Technologies Inc. sells for as little as $950, which works out to just over $237 per port.

    The price of Netgear Inc.'s $1,000 to $1,399 GS504 Series, with either copper or multimode fiber ports, comes to as little

    as $250 per port. D-Link Systems Inc.'s $1,295 DGS-3204 is a 1000Base-SX switch that figures out to $324 per port.

    There's no magic to choosing the right Gigabit Ethernet LAN switch'just carefully match your requirements with the appropriate feature sets.

    Flexibility. Fixed-port switches provide the same 1-Gbps throughput as any other Gigabit Ethernet switch, but they do not allow users to reconfigure the number and types of ports built into them.

    They are inexpensive, though, so if price and raw speed are your main criteria, I recommend one of the fixed four- or eight-port Layer 2 Gigabit Ethernet models listed.

    If flexibility is a key criterion, consider switches such as Alteon WebSystems' ACEswitch 180, Cisco Systems Inc.'s Catalyst 3550-12T or Hewlett-Packard's Procurve switch 8000m.

    They give you flexibility in the number and types of ports you use'for example, designating some ports for 10/100-Mbps Fast Ethernet'and offer modules that provide Layer 3 routing and higher levels of management capability.

    Make sure that if a switch offers 10-Mbps, 100-Mbps and 1-Gbps port options'typically listed as 10/100/1000'it can automatically sense the speeds of attached devices and set its port speeds accordingly.

    Autonegotiation, the ability to negotiate between half-duplex and full-duplex modes, is also important, as are hot-swappable switching modules.

    Layer 3 routing. Layer 3 switches combine advanced routing features with the raw speed of Layer 2 switches.

    Because they come with more costly components, such as application-specific integrated circuits (ASICs) and built-in RISC processors for handling routing calculations, they generally are more expensive than Layer 2 switches.

    But they usually are much richer in feature sets than Layer 2 devices. A Layer 3 switch with advanced routing protocols, virtual LAN support and quality of service features can be worth the extra money.

    If you decide to go the Layer 3 route, be sure the switch includes advanced routing protocols such as Routing Information Protocol and RIP Version II, Open Shortest Path First, Multicast IP and Internet Group Management Protocol.

    Layer 3 switches can also handle common Ethernet throughput problems such as broadcast storms more efficiently than Layer 2 switches can.

    Because Layer 3 is a pathway to layers 4 through 7 of the Open Systems Interconnection model, Layer 3 switches enhance data traffic management and quality of service.

    Scalability. Although the benefits and cost-effectiveness of small fixed-port switches are real, it is sometimes desirable to stack two switches or more to increase the number of available ports without limiting throughput rates.

    Setup and installation. Layer 2 fixed-port switches are often plug and play. You can get one running in minutes by plugging it in and making your port connections'but be sure Gigabit Ethernet cards are installed in end-user devices first.

    If you want Web-based management, you'll probably have to set up an IP address; most Layer 2 switches come with clear instructions on doing this.

    Gaining full Layer 3 functionality is more difficult, but by following the switch's menu closely you should be able to set one up without much hassle.

    Management. Managing and administering any switch listed should be relatively easy because they all come with proprietary management software based on Simple Network Management and Remote Network Monitoring protocols. Web management capability is important, particularly for Layer 3 switches.

    If your enterprise network includes umbrella network management systems such as HP OpenView, be sure the switch supports them.

    Redundancy. Though LAN switches typically don't require backup power sources and fault-tolerant components, some of the more expensive Layer 2 and Layer 3 switches provide them as options. You might never need them, but it's nice to know they are available.

    J.B. Miles of Pahoa, Hawaii, writes about communications and computers. E-mail him at jbmiles@gte.net.

    Gigabit Ethernet is likely to become standard fare in the networking world even before many organizations move from 10-Mbps Ethernet to 100-Mbps Fast Ethernet LANs.

    Because 10/100 Ethernet LANs running over Category 5 copper cable already dominate the industry, copper Gigabit Ethernet switches are a logical choice for managers building LANs to meet high bandwidth requirements.

    They also cost about one-third less than comparable fiber products. Prices for a few fixed-port 1000Base-T copper switches are less than $250 per port; some analysts predict this will drop to around $100 by next year.

    Just around the corner, 10-Gigabit Ethernet will migrate to the WAN and gradually replace Gigabit Ethernet as the technology of choice for network backbones.

    Although complete standards for 10-Gigabit Ethernet haven't yet been ratified, market analysts predict that more 10-Gigabit products, including switches, will appear on the market by the end of this year.

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