The bestselling classic continues to provide an enduring, practical understanding of networks and their building blocks through rich, example-based instruction. Using a systems approach, Larry Peterson and Bruce Davie continue to focus on the why of network design with a renewed emphasis on the application layer. The "Systems Approach" adopted by the authors looks at "the big picture," encouraging readers to consider networks as interactive complex systems rather than rigidly defined layers. Thought-provoking and updated problems are presented at the beginning of each chapter so that the student or professional can start to solve the issue with each new detail learned. With every chapter building on the last, readers' knowledge of tools and resources continually enhances. By the end, readers thoroughly understand how complex networks and their applications are built.*Completely updated content with expanded coverage of the topics of utmost importance to networking professionals and students, including P2P, mobility, security, and applications.*Increased focus on application layer issues where innovative and exciting research and design is currently the center of attention.*Free downloadable network simulation software and lab experiments manual available.