This book is the official supplemental textbook for the Introducing Routing and Switching in the Enterprise course in the Cisco® Networking Academy® CCNA® Discovery curriculum version 4. The course, the third of four in the new curriculum, familiarizes you with the equipment applications and protocols installed in enterprise networks, with a focus on switched networks, IP Telephony requirements, and security. It also introduces advanced routing protocols such as Enhanced Interior Gateway Routing Protocol (EIGRP) and Open Shortest Path First (OSPF) Protocol. Hands-on exercises include configuration, installation, and troubleshooting.