Network usage is continuing to accelerate as enterprise network users communicate via video-conferencing, develop products more collaboratively, and rely more heavily on networked tools. Top-Down Network Design, Third Edition presents a systematic, fully practical approach to designing networks that will keep pace with these changes. Thoroughly updated for todays newest technical and business trends, it covers all facets of enterprise network design and all elements of modern enterprise networks. The authors innovative top-down approach starts by focusing on applications and user requirements, and only then turns to technology selection. Readers will discover how to systematically analyze business and technical requirements, and then select topologies and technologies that reflect this analysis. The authors walk through designing campus networks, data centers, remote access, and wide-area connectivity, and designing for security in an era of wireless networks and mobile users. They also present detailed coverage of performance, reliability, and scalability. Graphics are used extensively throughout to clarify concepts and present examples This Third Edition includes new coverage of designing networks that comply with IT Service Management processes, as well as an updated glossary. It also adds chapter-ending essay questions and design scenari's for readers who want to test their understanding of key concepts.