There are a variety of ways to structure the most prevalent types of Internet failures. A first
crude classification one could make is into intentional failures (i.e., attacks) and unintentional failures. However, by analyzing the listed incidents and their causes, it becomes apparent that most Internet failures were unintentional, and only a few of the incidents were the result of malicious attacks. We therefore adopted a slightly different categorization into infrastructure failures, Border Gateway Protocol (BGP)-related failures, and service failures resulting from an attack. Each category is further subdivided as follows.