This document discusses enterprise network design and architecture. It outlines Cisco's enterprise architecture model, including hierarchy, modularity, resiliency and flexibility as key design principles. The model includes access, distribution and core layers. It also describes Cisco's enterprise campus, enterprise edge and service provider edge modules, and their sub-modules like building access, distribution and core, e-commerce services and internet connectivity. Finally, it mentions future challenges and Cisco's ONE enterprise network model as a solution.