Accessing the WAN, CCNA Exploration Companion Guide is the official supplemental textbook for the Accessing the WAN course in the Cisco Networking Academy CCNA Exploration curriculum version 4. This course discusses the WAN technologies and network services required by converged applications in enterprise networks. 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.