This chapter introduced the concept of basic network design "building blocks" and follows that concept by building out a typical campus design using the three-tiered core, distribution, and access layer design model. Traffic flows and redundancy options are explored by examining link redundancy, and by examining supervisor and switch fabric redundancy options on each major switching platform. Chapter 12, "Troubleshooting the LAN Switching Configuration," examines techniques used to troubleshoot an existing Catalyst switching network.