Data Communications Networking Devices - 4th Ed.pdf

xxiv _______________________________________________________________________ PREFACEThe new chapter covering wide area networks ®rst explains the different types ofnetworks and then examines network architecture and the ¯ow of data in severalpopular networks. Similarly, the new chapter on LANs provides a solid foundationconcerning the topology, access methods, and operation of several types of popularlocal area networks, laying the groundwork for detailed information concerning theoperation of WAN and LAN internetworking devices presented in later chapters inthis book.Similar to prior editions of this book, this edition was structured for a twosemester course at a high level undergraduate or ®rst-year graduate course level. Inaddition, this book can be used as a comprehensive reference to the operation andutilization of different networking devices and as a self-study guide for individualswho wish to pace themselves at their leisure.As I once again rewrote this book, I again focused attention upon explainingcommunications concepts which required an expansion of an already comprehensiveintroductory chapter into a series of three chapters in order to cover thefundamental concepts common to all phases of data communications. All threechapters should be read ®rst by those new to this ®eld and can be used as a reviewmechanism for readers with a background in communications concepts. Thereafter,each chapter is written to cover a group of devices based upon a commonfunction.Through the use of numerous illustrations and schematic diagrams, I believereaders will easily be able to see how different devices can be integrated intonetworks, and some examples should stimulate new ideas for even the mostexperienced person. At the end of each chapter I have included a comprehensiveseries of questions that cover many of the important concepts covered in thechapter. These questions can be used by the reader as a review mechanism prior togoing forward in the book.For those readers actually involved in the sizing of network devices I haveinclude several appendices in this book that cover this area. Since the mathematicsinvolved in the sizing process can result in a considerable effort to obtain therequired data, I have enclosed computer program listings that readers can use togenerate a series of sizing tables. Then after reading the appendices and executingthe computer programs, you can reduce many sizing problems to a table lookupprocedure. As always I look forward to receiving reader comments, either thoughmy publisher whose address is on the back cover of this book or via email to 235-8068@meimail.comGilbert HeldMacon, Georgia