Switch to the Future

Ethernet has surpassed all other networking technologies in speed, scalability and ease of implementation. It has become the global standard for networking because it provides a consistent and standardized pathway from data centers and high-end servers across LANs, WANs and MANs to user desktops. In its Gigabit and 10-Gigabit forms, it can handle all types of bandwidth-intensive applications such as voice over IP (VOIP), streaming video, medical imaging and high-end graphics, plus the burgeoning demands of the Internet.Today's class of 10-Gigabit Ethernet and Gigabit switch/routers represent third-generation devices designed to keep pace with the real-world requirements of high-speed Ethernet networking. Called variously Layer 3 switches, multilayer switches, routing switches, switching routers or gigabit routers'depending on who is describing them'they all pack switching and routing functions into the same chassis.Switch/routers operate at both Layers 2 and 3 of the Open Systems Interconnection model. Layer 2 switches forward traffic based on physical network ad- dresses, meaning they look up a packet's Media Access Control address and forward it accordingly. Because they handle relatively low-level information, they are blindingly fast, but they aren't very smart because they don't know what the packets they forward contain.Layer 3 devices connect networks, not just devices, so they are generally more intelligent than Layer 2 switches. They determine the best path over the network to a destination host by looking at the header portion of an incoming packet, which contains the recipient's network address.[IMGCAP(2)]Newer switch/router models, capable of providing Layers 4 through 7 switching, are sometimes called content-aware be- cause they are capable of providing application-level information to users. Gigabit Ethernet networks and delay-sensitive, high-bandwidth applications such as voice over IP, video and iSCSI all benefit from Layer 4 classification, which allows session-by-session quality of service and end-to-end session management.Today, the demand for both Gigabit and 10-Gigabit products is robust and growing. According to a report by the Dell'Oro Group, a high-tech market research company in Redwood City, Calif., shipments of Gigabit ports exceeded those of Fast Ethernet ports for the first time in 2004, and shipments of 10-Gigabit ports grew more than 70 percent in two straight quarters last year.'Attractive price points are making the decision to upgrade to modular Gigabit a relatively easy one for many enterprises, as the total per-port average selling price of modular Gigabit is currently only twice that of modular Fast Ethernet,' said Seamus Crehan, director of Ethernet switching for Dell'Oro. 'Much of the growth in this segment is driven by larger enterprises deploying modular gigabit-over-copper in their wiring closets, which in turn is driving demand for 10-Gigabit Ethernet to aggregate this traffic.'For agency buyers, the single most important feature of any new switch/router is whether it is IPv6-ready. IPv6 is the next-generation Internet Protocol and is designed to remedy the shortcomings of IPv4. It increases address size and offers better features, such as built-in security and quality of service.[IMGCAP(3)]'The demand for full IPv6 support, including routing, QoS, access control lists and IPv4 to IPv6 transition mechanisms, is an es- sential capability for high-performance Ethernet systems,' said Gary Smerdon, CEO of Greenfield Networks Inc. of Sunnyvale, Calif., which sells high-end chip sets for Gigabit and 10-Gigabit switches.IPv6 has been mandated for use in federal agencies by 2008 and already comes with, or is pending in, most of the high-end 10-Gigabit switch routers in our guide. About half are currently IPv6-ready.In general, 10-Gigabit switches are designed for large enterprises and service providers. Some, such as the Enterasys Matrix-N Series, are designed to support core or edge routing at 10-gigabit rates, with services such as advanced quality of service for data prioritization, and granular control of bandwidth provisioning. Others, such as Broadcom Corp.'s new StrataXGS 600, are carrier-class switch/routers with multiprotocol label switching, service provider bridging, stacked Layer 2 services and other features.[IMGCAP(4)]Overall, their sheer size, performance capabilities, scalability and high price tags define 10-gigabit behemoths. For example, Foundry Networks Inc.'s $26,246-plus BigIron MG8 offers wire-speed 480Mbps routing and eight interface slots with up to 96 10-gigabit or 1,440 gigabit ports per seven foot rack'and that's by no means the largest switch the company makes.Of course, not every network requires 10-gigabit service. 100Mbps Gigabit Ethernet continues to be the Ethernet of choice for many enterprises, particularly at network edges where gigabit speeds translate well into cost-effective throughput. And because not all applications re- quire gigabit-scale speeds to the desktop, many Gigabit switches provide 10/100/1000 combo ports that can be scaled up or down as required.Gigabit switches are noteworthy for their smaller feature sets, performance capacities tailored to smaller network segments and affordable prices. They may be used anywhere in the network, including edge deployments and branch offices, small enterprise core switching, data centers, and even for mission-critical workgroups or LAN wiring closets.The Gigabit switches included in this guide generally include between 24 and 48 combo ports, often with two or four Gigabit stacking ports. Most of them are stackable, and can handle up to eight units per rack.While most of these units, generally priced between $1,200 and $5,000, come with a fairly robust set of management and security features, don't expect the same quality of service, virtual LAN support and redundancy that you'll find in the big guys.Another big difference between current-generation 10-Gigabit switch/routers and Gigabit Ethernet switches is a fundamental difference in design. The larger switches are chassis-based, meaning they can accommodate up- graded line, fabric and supervisor cards for higher-speed ports and greater processing capabilities. Most gigabit switches are stackable, but without replaceable line cards, they cannot be as easily modified or upgraded as chassis-based models can. In most cases, when you wish to add more feature sets, you'll have to purchase new switches.J.B. Miles writes from Honomu, Hawaii. E-mail him at .