The Move Toward Gigabit LANs
Organizations have long used Local Area Networks (LANs) to share applications and equipment across workgroups. Ethernet, the networking standard pioneered by Intel, Digital and Xerox, has become the most commonly used LAN technology worldwide. More than 85 percent of all installed network connections are Ethernet, according to International Data Corporation (IDC).
In the past few years, high-bandwidth applications and high-speed communications between networked users have driven major increases in desktop computing power, first to Fast Ethernet and now to Gigabit Ethernet. This trend is expected to continue, spurred in part by the rapid growth of e-Business and the rapid adoption of Fast Ethernet in workgroups.
The Role of the Internet
Gartner Group estimates that by 2005, 25 percent of consumer spending and 70 percent of business-to-business commerce will be "Internet-involved." In addition, many companies are building intranets where employees can gather business information using Internet technology. These changes are fostering new, bandwidth-intensive multimedia applications encompassing voice, video and data - applications that are used all the way down to the desktop level. Other demanding applications range from scientific imaging to data warehousing.
With applications requiring greater bandwidth at the desktop, and with the number of users continuing to grow, more and more organizations have chosen to migrate to high speed networking technologies. Fast Ethernet, which runs at 10 times the rate of Ethernet, has become the most popular choice. By building on the original 10BASE-T Ethernet standard, Fast Ethernet provides an affordable, non-disruptive transition from 10 Mbps to 100 Mbps.
However, the growing use of Fast Ethernet connections to high performance desktops has created the need for an even more powerful technology higher up the network. A typical network is analogous to the plumbing in a house, where many smaller pipes connect to fewer medium-sized pipes, which in turn connect to one large pipe accessing the local water supply. By the same token, if many desktops all need to access a server through the same pipe, then that pipe should be large enough to carry several times the bandwidth of a desktop.
Accordingly, migration to Gigabit Ethernet is beginning to grow even as the pace of Fast Ethernet adoption continues to accelerate.
Setting the Stage
Several factors contribute to setting the stage for Gigabit Ethernet:
- Many of today's PCs are "future-proofed" with 10/100 connections. The number of 10/100 PC users running Fast Ethernet is growing rapidly (Figure 1). And with 100 Mbps bandwidth at the desktop, even greater bandwidth is required at the server and backbone levels. According to Infonetics, an estimated 71 percent of desktops will be running at 100 Mbps by the end of 2000.
- A majority of high performance LAN purchases are driven by server bottlenecks and the addition of new servers to the network (Infonetics, '99). Today's servers can process larger files and move more data faster than ever before, but the network and its server connections must support this performance.
- Thanks to Internet technologies and applications, as well as today's centralized data center model, about half of all network traffic now travels across IP or IPX subnets. This traffic must be aggregated at the backbone levels before it is moved out across subnets and eventually out onto the WAN. This has increased the need for high performance, bandwidth-intensive switches that are capable of Layer 3 routing.
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| Figure 1. Trends in Desktop Speed |
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The most appropriate solution to these challenges is 1000 Mbps Gigabit Ethernet, which offers a natural upgrade path for current Ethernet and Fast Ethernet installations. Gigabit network adapters are needed to prevent bottlenecks from developing at high-demand servers, and Gigabit uplinks and switches are needed to aggregate Fast Ethernet traffic at switch stacks and the network backbone.
In the future, Gigabit LANs are expected to be the norm. In the meantime, LAN managers are looking for ways to future-proof their networks for 1000 Mbps and move critical segments to Gigabit now. The recent adoption of the 1000BASE-T standard, which allows deployment of Gigabit Ethernet over Category 5 (CAT 5) copper cabling, has helped facilitate these efforts.
Industry Standards
As networking has progressed, so have industry standards. Gigabit Ethernet has evolved from the original 10 Mbps Ethernet standard, 10BASE-T, and the 100 Mbps Fast Ethernet standards, 100BASE-TX and 100BASE-FX. A 10 Gigabit Ethernet standard is already planned.
In June of 1998, the IEEE approved Gigabit Ethernet over fiber optic cable as IEEE 802.3z, and its implementation was widely supported by networking vendors.
With adoption of 802.3z, companies could rely on a well-known, standards-based approach to improve traffic flow in congested areas.
A year later, in June of 1999, the IEEE further standardized IEEE 802.3ab Gigabit Ethernet over copper as 1000BASE-T, allowing Gigabit speeds to be transmitted over Category 5 cable (Figure 2).
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| Figure 2. Gigabit Ethernet Standards |
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