IS-IS Network Design Solutions

Introduction to IS-IS Routing Protocol

The Intermediate System-to-Intermediate System (IS-IS) Routing Protocol is a versatile and robust routing protocol suitable for both IP and CLNP applications. In the world of IP, IS-IS has emerged as the only practical alternative to the Open Shortest Path First Protocol (OSPF) for Interior Gateway Protocol (IGP) applications, particularly in Internet Service Provider (ISP) networks. It is the IGP of choice in most Tier One ISP environments, which explains its significance in exams such as the CCIE Routing and Switching and CCIE IT recertification exams. Despite its importance in IP networking, IS-IS has received little coverage in technical publications and networking literature. You can learn more about this protocol by joining the Lab Courses offered by SPOTO.

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Challenges in Understanding IS-IS

Most users and networking professionals rely on limited literature, such as configuration manuals from Cisco and other major router vendors, to deepen their knowledge of IS-IS. While many routing protocol texts from Cisco Press include sections on IS-IS, OSPF tends to dominate many other book titles. The book IS-IS Network Design Solutions breaks this tradition by focusing primarily on IS-IS. It follows the popular Cisco Press approach of combining theory and practical applications within a Cisco Routing environment. The text also provides an elaborate comparison between IS-IS and its competitor, OSPF.

IS-IS and Its Role in Network Design

Interior Gateway Protocols such as IS-IS are used alongside the Border Gateway Protocol (BGP) to ensure robust, resilient performance, and intelligent routing capabilities in large-scale and complex internetworking environments. Despite the widespread use of IS-IS, networking professionals have largely relied on router configuration manuals, protocol specifications, IETF RFCs, and drafts to learn about the protocol. For many, mastering IS-IS, despite its relatively simple nature, remains a daunting task.

Comprehensive Coverage in IS-IS Network Design Solutions

IS-IS Network Design Solutions will provide the first comprehensive coverage of the IS-IS protocol. Networking professionals of all levels will have a single source of information to become true experts on the IS-IS protocol, especially for IP routing applications. The book begins by exploring the origins of the IS-IS protocol and its fundamental concepts, and gradually advances to more complex protocol mechanisms, such as building, maintaining, and disseminating the information stored in the IS-IS database on a router.

Objectives of IS-IS Network Design Solutions

The primary objective of this book is to provide comprehensive knowledge about the IS-IS routing protocol to IP networking professionals at any stage in their career. Just like other IP routing protocols, IS-IS continues to evolve, with new enhancements being discussed and formalized by the IETF. The book bridges the original IS-IS protocol—designed for routing the ISO Connectionless Network Protocol (CLNP)—with the latest IP-related enhancements. Its practical approach, utilizing the ubiquitous Cisco IOS environment, will offer hands-on experience in using and configuring the IS-IS protocol. The material is designed to equip you with the advanced skills needed to understand, design, and apply IS-IS as an IGP in IP environments.

Hands-on Experience for CCIE Lab Preparation

To fully achieve the objectives outlined in this book, theoretical knowledge alone will not suffice. Hands-on lab practice is essential. This practice can be gained through the CCIE Lab Preparation Courses offered by SPOTO. SPOTO is a one-stop destination for all Cisco-related certifications, providing both knowledge and hands-on practice to help you clear your CCIE Lab Exam​.