The Cisco Wide-Area Application Engine family includes three network modules for the Integrated Services Router and six appliance models spanning two desktop models and four rack-mount appliance models. This breadth of portfolio provides customers with the flexibility necessary to allocate the right platform for each network location where WAN optimization, application acceleration, and virtualization capabilities are needed. Four licenses are available for Cisco WAAS, including the Transport license (WAN optimization capabilities only), Enterprise license (all application accelerators except video, and certain other features), Video (Windows Media over RTSP stream splitting), and Virtual-Blades (branch office virtualization platform). Sizing of a Cisco WAAS solution requires consideration of a number of factors, including network conditions (WAN bandwidth and LAN throughput), number of users and concurrent optimized TCP connections, disk capacity and compression history, memory, concurrently connected peers, and virtualization requirements. By following the recommended guidelines for performance and scalability, a robust Cisco WAAS design can be realized, thereby allowing administrators to deploy the solution confidently to improve application performance over the WAN while enabling centralization and consolidation of costly infrastructure.