The IS-IS routing protocol has gone through a high-speed evolution in recent years. Initially deployed by the largest ISPs in a desperate search for a stable link-state protocol, it quickly gained popularity for its advantages in link-state routing. Today, it is a widely deployed protocol even at smaller ISPs but because of its meteoric adoption it has been sparsely documented. As service providers add multivendor platforms from both Cisco and Juniper Networks, it is difficult to get acomplete picture of the IS-IS that is deployed in the field. As service providers deploy increasingly multivendor implementations of IS-IS, they desperately need to know how to interoperate the protocol on different routing platforms. Only a book such as TheComplete IS-IS Routing Protocol can provide the insight and practical solutions necessary, because it takes a multivendor, real-world competitive approach to implementing IS-IS. TheComplete IS-IS Routing Protocol will be the seminal book on IS-IS for many years to come.