Category list

Acknowledgments

Writing your first book is a daunting and challenging experience, and now is the time to recognize that we did not do this alone. We would like to thank the technical reviewers ”Ray d'Urso, David Weal, and Scott Reeves ”for their invaluable technical and literary input. Thanks also to Mary Franz and her team at Prentice Hall for their interest, encouragement, and guidance over the past 12 months. While we have kept this book as an independent view of the content switching space, we are also both indebted to the efforts of those people behind the scenes at Alteon WebSystems and Nortel Networks who create the tools we use.

I would like to thank my family and friends , all of whom have offered love and encouragement not only during the task of writing this book, but in everything I do. This is my time to say thank you for all your love and support. All my love to Fleur, who put up with many long weeks and months of tapping keys and a furrowed brow ”thanks.

Philip Goldie, December 2002

During my career I have come across many individuals who have assisted and helped me learn and better myself ”to those people I say thank you. I hope I have been able to provide something back to others who have worked with me over the years. I would like to thank Ray d'Urso who has had significant influence in my learning and made me look at problems from outside the square. It has been a privilege to have him review this book. Also to my family for their love and support over the years , and in particular, Debra, Jessica, and Cameron for hanging in there during those long evenings. To all, I say thank you.

Matthew Syme, December 2002

Summary

While writing a book on a topic that is new and exciting and one that allows even the most seasoned professional to experience some sort of satisfaction after completing a difficult configuration or finally solving an impossible problem, we have tried to ensure that we have covered the technical aspects, including the advantages and disadvantages of content switching, without discussing vendor-specific configurations and CLI commands, and so forth. Our aim throughout has been to discuss the power and benefits of this technology. While this is a technology with which we are proud to be associated, it does not solve all problems and has many areas that need attention and better design and planning. Regardless, content switching opens a whole new area that allows us to extend our knowledge, enhance our skills, and, hopefully, in the process have some fun. We hope that you find this book a useful addition to your reference library.

Chapter 1. Introduction to Content Switching

Content switching, server load balancing, intelligent switching, Layer 4 switching, session switching, application switching. Like any maturing technology, no one name has been accepted to encompass all that content switching covers. We will use the term content switching throughout this book, as it appears to be the most commonly used method by which to express this technology. However, please understand that even this might change depending on what your requirements are.

Therefore, before we begin our journey through the workings and terminology of content switching, we should first pause and understand where and how this technology evolved.

Without a doubt, the roots of content switching can be tied directly to the growth of the Internet in the late 1990s, where Ethernet and TCP/IP became the king of the corporate networks. Suddenly, network manufacturers were not focusing their research and development staff on Token Ring, ATM, or FDDI, or protocols such as IPX, SNA, or NetBIOS, but rather on how to leverage this new and growing phenomenon that was being driven by the unilateral acceptance of TCP/IP and Ethernet across the globe.