Routing Protocols and Concepts, CCNA Exploration Companion Guide is the official supplemental textbook for the Routing Protocols and Concepts course in the Cisco Networking Academy® CCNA® Exploration curriculum version 4. This course describes the architecture, components, and operation of routers, and explains the principles of routing and the primary routing protocols. The Companion Guide, written and edited by Networking Academy instructors, is designed as a portable desk reference to use anytime, anywhere. The book’s features reinforce the material in the course to help you focus on important concepts and organize your study time for exams.