Book excerpt: The definitive IS-IS reference and design guide Extensive coverage of both underlying concepts and practical applications of the IS-IS protocol Detailed explanation of how the IS-IS database works and relevant insights into the operation of the shortest path first (SPF) algorithm Comprehensive tutorial on configuring and troubleshooting IS-IS on Cisco routers Advanced information on IP network design and performance optimization strategies using IS-IS Network design case studies provide a practical perspective of various design strategies Comprehensive overview of routing and packet-switching mechanisms on modern routers A collection of IS-IS packet formats and analyzer decodes useful for mastering the nuts and bolts of the IS-IS protocol and troubleshooting complex problems Interior gateway protocols such as Intermediate System-to-Intermediate System (IS-IS) are used in conjunction with the Border Gateway Protocol (BGP) to provide robust, resilient performance and intelligent routing capabilities required in large-scale and complex internetworking environments. Despite the popularity of the IS-IS protocol, however, networking professionals have depended on router configuration manuals, protocol specifications, IETF RFCs, and drafts. Mastering IS-IS, regardless of its simplicity, has been a daunting task for many. IS-IS Network Design Solutions provides the first comprehensive coverage available on the IS-IS protocol. Networking professionals of all levels now have a single source for all the information needed to become true experts on the IS-IS protocol, particularly for IP routing applications. You will learn about the origins of the IS-IS protocol and the fundamental underlying concepts and then move to complex protocol mechanisms involving building, maintaining, and dissemination of the information found in the IS-IS database on a router. Subsequent discussions on IP network design issues include configuration and troubleshooting techniques, as well as case studies with practical design scenarios.