Scaling Networks Companion Guide is the official supplemental textbook for the Scaling Networks course in the Cisco® CCNA® Academy® This course describes the architecture, components, and operations of routers and switches in a large and complex network. You will learn how to configure routers and switches for advanced functionality. By the end of this course, you will be able to configure and troubleshoot routers and switches and resolve common issues with OSPF, EIGRP, STP, and VTP in both IPv4 and IPv6 networks. You will also develop the knowledge and skills needed to implement DHCP and DNS operations in a network. The Companion Guide is designed as a portable desk reference to use anytime, anywhere to reinforce the material from the course.