This document provides an overview of the contents of the Sybex CCNA certification course. It outlines topics covered like TCP/IP fundamentals, routing, switching, VLANs, and security. It also describes the chapters and objectives, including internetworking basics, layered models, the OSI model, Ethernet networking, and data encapsulation. Cisco's three-layer model is introduced along with examples of switches, hubs, and cabling in a network. Review questions assess understanding of broadcast domains, collision domains, and simultaneous host transmissions.