Routing and Switching Essentials Companion Guide is the official supplemental textbook for the Routing and Switching Essentials course in the Cisco® Networking Academy® CCNA® Routing and Switching curriculum.This course describes the architecture, components, and operations of routers and switches in a small network. You learn how to configure a router and a switch for basic functionality. By the end of this course, you will be able to configure and troubleshoot routers and switches and resolve common issues with RIPv1, RIPv2, single-area and multi-area OSPF, virtual LANs, and inter-VLAN routing in both IPv4 and IPv6 networks.