Audience

I have written this book primarily for those engineers and network architects who know OSPF but would like to learn more about IS-IS. For this reason, you will find that for each chapter or section topic I almost always discuss OSPF first, and then IS-IS: The idea is to start you off on familiar ground, discussing how the topic at hand is implemented in OSPF, and then showing how it is implemented in IS-IS.

The book will also be helpful to those who do not already have a rich understanding of OSPF. Perhaps you know OSPF or IS-IS or both at an intermediate level, and you want to deepen your understanding of both protocols. Or perhaps you are one of those rare engineers who knows IS-IS but not OSPF. I have detailed both protocols equally to meet any of these needs.

You will also find the book educational if you are a beginning-level networker who wants to expand your knowledge of link state protocols. Chapter 2 in particular is written for you, to get you through the essential concepts of routing protocols in general and link state protocols in particular, so that you are prepared to tackle the remainder of the book. The chapters are arranged so that they take you from foundation concepts to increasingly more complex ones.

Finally, if you are preparing for a network certification such as Cisco Systems' CCIE or Juniper Networks' JNCIE, you will gain in these pages the essential conceptual understanding of OSPF and IS-IS needed to do well on the test. Configuration and troubleshooting exercises are beyond the scope of this book, however, and you will need to practice solving them via another resource to prepare fully for a certification exam. Review questions are included at the end of each chapter of this book to help you test your comprehension and retention of concepts before moving on to the next chapter. Because the answers are well documented in the body of the chapter, a separate answer sheet is not included.