IPSec VPN Design consists of three main sections. The first section provides a comprehensive introduction to the IPSec protocol, including IPSec Peer Models. This section also includes an introduction to site-to-site, network-based, and remote access VPNs. The second section is dedicated to an analysis of IPSec VPN architecture and proper design methodologies. Peer relationships and fault tolerance models and architectures are examined in detail. Part three addresses enabling VPN services, such as performance, scalability, packet processing, QoS, multicast, and security. This book also covers the integration of IPSec VPNs with other Layer 3 (MPLS VPN) and Layer 2 (Frame Relay, ATM) technologies; and discusses management, provisioning, and troubleshooting techniques. Case studies highlight design, implementation, and management advice to be applied in both service provider and enterprise environments.