Layer 3 switching is the next generation of LAN routing and switching technology - capable of transmission speeds up to ten times as fast at one-tenth the cost of current systems. Layer 3 Switching: A Guide for IT Professionals is the first systematic guide to this new technology. It presents clear criteria, business models and proven techniques for evaluating L3 switching products - and for planning and managing their implementation.
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ForewordBackground and Purpose
In the 1980s, bridges were deployed to connect disparate LAN segments in a simple and inexpensive manner. Routers were also introduced-to create structure and to add functions-but these often turned out to be complex or expensive. Network managers struggled to learn how to design optimal networks using this new routing technology, as well as how to choose among differing approaches to routing. In addition, some vendors who did very well selling bridges did not adjust to the demand for routers, and lost significant market share.
A similar phenomenon is in progress with Layer 2 (L2) and Layer 3 (L3) switching today. From a technology perspective, L2 switches are similar to bridges and have similar characteristics; i.e., they are low-cost and easy to use. Over the last three years the L2 switch market has grown from nonexistent to one worth multiple billions of dollars. Routing functions, though, are still required in our networks. L3 switches promise to fulfill these requirements, but in a manner that is faster, easier, and less expensive than routers of the past.
Your authors believe that the industry will struggle to deploy L3 switches in the same way it struggled with routers. Network Professionals will have to contend with four problems:
It is a lot more difficult to get approval and funding for upgrades to an existing network than for initial deployment.
There are several different approaches to designing networks using L3 switches.
Vendors have implemented L3 switching in a myriad of ways. As a general rule, multiple alternatives in a marketplace confuse buyers, who often react by not purchasing the new products.
People are often suspicious about the introduction of new technology. There is too much history in our industry of hyped technology that ultimately fails in the marketplace (e.g., 100VG-AnyLAN, ATM-25).
As long as prospective buyers struggle, vendors will not prosper. In particular, if network professionals can not distinguish among L3 approaches, design their networks with L3 products, and justify network upgrades to management, then vendors cannot sell products to them. In addition, we see vendors often totally self-absorbed in their own approaches to the marketplace, when they really need to be able to place their approaches in a broader context of what network managers need and what competitors are offering.
Our goal in this book is to cut through the intellectual pollution that surrounds the introduction of new technology in general, and the introduction of Layer 3 switching in particular. We provide buyers with the context for evaluating how L3 switching applies to their unique situations. We also provide details about the technology and about selected vendor implementations and products. For vendors, the book provides context in which to better understand the issues faced by potential customers in buying and deploying products. It also provides vendors with a framework for positioning their products relative to the broader marketplace.Scope and Coverage
Today's society is characterized by some as "information-based" and by others as "knowledge-based." We see today's economy increasingly as "global" rather than regional or national. Coupling these with various "time-is-money" and competitive business pressures, it is hardly surprising that we expect more and more from our communications infrastructure in terms of providing timely access to critical information. Computers and networks have become central to the functional and competitive character of many diverse businesses and organizations. From automated factories to electronic storefronts, from Enterprise Resource Planning (ERP) to on-line reservations, from digital libraries to personal web sites, reliable and effective networks are becoming fundamental to how we work and live. "The more we have the more we want" is turning into "the more we have the more we need." As your authors have traveled over the past year, we have not met anyone from a viable business or organization who was expecting his or her network to shrink over the next year or so. More powerful computers in the hands of more skilled people using them for more, simple and sophisticated applications continue to drive up demands for capacity, performance, and reliability. The impact of all these ramifications is discussed further in Chapters 2, 3, and 8.
Have you ever worked in an environment where new technology was "pushed" by advocates, sometimes for its own sake, rather than being "pulled" by business requirements? Have you ever worked for a company where product development was driven by engineering interest without regard for market potential? Have you ever worked with people who absolutely needed the latest computer hardware or software, but only because someone else had it? If so, you may be keenly aware of how inflated technology promises often are, whether positive or negative. Word processing tools did not really eliminate many secretarial positions and automated tellers have not eliminated the need for traditional bank offices. Nor have television and computers revolutionized how we educate the majority of students, and most people know how to use only a small fraction of the functional capabilities of their application programs. Computing, and networking in particular, have often been accused of over-promising and under-delivering. Yet there are well-know examples of dramatic successes, too-American Hospital Supply, American Airlines, and Frito-Lay, to name a few. While this book provides a lot of coverage for a particular new technology (Layer 3 switching is covered in depth in Chapters 4-6), you may find the criteria in Chapter 2 for assessing fundamentally new technologies to be valuable in a much broader context (Table 2.5.1).
Chapter 7 provides several network designs using Layer 3 products in response to a particular case study developed by Strategic Networks. While the case may not resemble your own or your customers' environments, you may find the process laid out in Chapter 2 for evaluating the appropriateness of a new technology (Table 2.7.1) to be quite relevant to understanding which pieces of the study apply to your situation. Formalizing some of these steps and involving network stakeholders can help minimize the risks of introducing new technology into a network that has become critical to the successful operation of an enterprise.
Finally, Chapter 9 draws everything together with our suggestions for the "top ten" issues one umust address in order to be successful in the deployment or sale of Layer 3 switching products. We also point out which ones generalize well to a larger context. With any luck, some of these ideas will help to minimize the risks of applying Layer 3 technology today, as well as other new technologies in the future.Guidelines for Readers
This book is aimed primarily at people in organizations who are struggling to upgrade their LAN infrastructures. We think you can get value from the following:
Planning methodologies and evaluation criteria that apply not only to L3 switching, but also to successful evaluation and deployment of virtually any new technology;
Explanations in depth of the spectrum of approaches to Layer 3 switching;
Suggestions for how the various L3 approaches address three common networking problems: evolving the collapsed backbone, evolving the server farm, and migrating beyond FDDI.
This book is also useful for vendor personnel who are tasked with positioning their products in the marketplace. It can help identify their opportunities and challenges in the customer environment: what is in place today, what is driving or inhibiting change, and what criteria are being used to evaluate L3 technology. It can also provide the background necessary to position their own products relative to the myriad of technologies and other products in the marketplace.
No introduction would truly be complete without some notes of caution. The pace of change in computer and networking technology is not likely to slow, although we do sometimes wonder if it can continue to accelerate forever. Consequently, it is important to note that the product details covered in this book, and to some extent, the information on Layer 3 technologies, represent a snapshot in time that may be accurate for a relatively short period. The technology will evolve; the products will be enhanced or new versions will supplant the ones discussed. We are quite confident, however, that the methodology the book presents for evaluating new technologies will continue to be useful. You can test this for yourself as vendors begin to discuss their approaches to "Layer 4 switching."
It is also worth mentioning that we did not even attempt to cover all L3 switching approaches or all available products in this book. Our selection of major vendors in terms of market leadership and interesting products from start-up companies could not possibly please or agree with everyone else's choices. We do think that our selection represents a good diversity and our analysis will help you to evaluate others if you are a prospective buyer. For vendors not covered here, you get a glimpse of who we think your major competition is today.
We do not consider this to be a technical book, despite the fact that it is about a particular technology. We may have provided more technical detail than some of you ever want to know about Layer 3 switching, for others we probably have not provided enough. Our goal is to provide some structure for how to think about L3 and a framework which you can use to evaluate this and other new technologies. It has been a challenging project, and we invite you to share the enthusiasm and concerns we have incorporated here.From the Back Cover:
The first comprehensive, objective guide to Layer 3 switching
Layer 3 switching is the next generation of LAN routing and switching technology-capable of transmission speeds up to ten times as fast at one-tenth the cost of current systems. Layer 3 Switching: A Guide for IT Professionals is the first systematic guide to this new technology. It presents clear criteria, business models and proven techniques for evaluating L3 switching products-and for planning and managing their implementation. Coverage includes:
* How to determine whether Layer 3 switching really makes sense for your organization
* Top 10 issues you must address to successfully deploy Layer 3 Switching
* Real-world network designs incorporating Layer 3 switching
* Practical explanations of what Layer 3 Switching is-and what it is not
* Key differences between packet-by-packet L3 switches and L3 flow switches
Discover how L3 switching can be used to evolve today's overtaxed server farm and collapsed backbone networks. Learn how L3 switching can be used to supplement FDDI to support applications that demand high bandwidth and high reliability. Compare today's leading approaches, with extensive examples of current products-including detailed real-world benchmarks for six L3 switches. Finally, understand your options for managing L3 switches once you've implemented them.
Whether you're a network manager, professional, or consultant, if you need better LAN performance, you need this objective, no-hype guide to Level 3 switching.
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Book Description Prentice Hall, 1998. Hardcover. Book Condition: New. Bookseller Inventory # DADAX0139198385