The document is a chapter from a Cisco textbook that introduces switched networks. It discusses the convergence of data, voice and video networks and the benefits of a single, converged network. It describes the core, distribution and access layers of hierarchical network design and how switches use MAC address tables, store-and-forward or cut-through switching to segment networks into separate collision domains while maintaining a common broadcast domain. The chapter objectives are to explain switched network design and frame forwarding processes.