"The update to Data Communications And Networking by Behrouz Forouzan provides a thorough introduction to the concepts that underlie networking technology. This update provides two new chapters on topics of growing importance. Chapter 26 covers VLANs and VPNs, and chapter 27 covers the increasingly important topic of network security. Forouzan's approach is accessible to students without technical backgrounds, and also provides material comprehensive enough to challenge the more experienced student. The seven-layer OSI model is used as a framework to provide the background necessary for explaining networking theory and showing interlying dependencies. The second edition of Forouzan's Data Communications and Networking includes new exercises and some more challenging ones. In addition, he has increased coverage of some new topics in networking such as some of the new encoding systems, fast Ethernet, 100VganyLan, ADSL and DSL. Key features The book teaches data communications and networking to students without heavy technical background while still providing challenges to more experienced students. In the second edition, new technologies have been added to make the book up-to-date, such as switched ethernet, cable modem, subnetting, and masking The seven layers of the OSI model have been chosen as the foundation of the text. More than 700 figures provide complete, visual presentation of the material. Many examples have been developed in each chapter to demonstrate the concepts. Summaries at the end of each chapter emphasize the key points Key terms have been added to the end of each chapter in the second edition. The practice set now includes review questions, multiple choice questions, and extended exercises. Appendices are added for quick reference and review of material needed to understand the concepts discussed in the book. A full solutions manual is available for all review questions, multiple choice questions, and exercises. Multicolor powerpoint presentation is available online. "