This new book outlines and establishes a comprehensive framework for network security which unifies the many definitions of network security and enables users from all sectors to employ the same framework to discuss, compare, and implement network security. The book presents an example wherein the framework is utilized to integrate security into the operation of a network. As a result of the integration, the inherent attributes of the network may be exploited to reduce the impact of security on network performance and the security availability may be increased down to the user level. The example selected is the ATM network which is gaining widespread acceptance and use. An integrated, security-on-demand system is first modeled, then simulated extensively on a large-scale asynchronous distributed simulator, and finally, the performance results are detailed.