Designing an efficient, cost-effective network that meets or exceeds the requirements is no easy matter. Today's equipment and technologies are becoming increasingly diverse and have the alarming property of becoming "old technology" almost as soon as they are installed. Mistakes can be, and often are, expensive. This chapter provides some basic definitions and introduces the concepts of a design process, the intention of which is to ensure that the design develops in a structured way, with all relevant data exposed during the process so that there are no late surprises. It resembles Chapter 1 of High-Performance Network Design: Design Techniques and Tools [1], and has been included for the sake of completeness. This chapter also introduces the basic hardware and software building blocks used in the construction of modern network designs.

1.1 Network design and performance

No two people agree exactly on what network design is. Network design is a generic and often subjective term that covers a whole range of skills and tasks, from the logical design elements (such as network protocols, addressing, subnetting), down to the physical design elements (such as physical topology, traffic modeling, circuit infrastructure). This book attempts to provide a holistic approach to network design by covering all the essential elements from the ground up. Whatever be your particular perspective at this point in time, by the end of this book you will get an appreciation of the subject as a whole.