WAN Technologies CCNA 4 Companion Guide is the official supplemental textbook for the CCNA 4 course of the Cisco Networking Academy Program‎.‎ Completely revised from the previous edition with new examples and explanations‎,‎ this textbook includes original material developed by the author‎,‎ yet it fully aligns with the CCNA 4 curriculum‎.‎ Written by an experienced author who present material in a comprehensive manner‎-‎-using his own voice and own examples‎-‎-this new edition augments student understanding of course material‎.‎ The new edition incorporates improved features to aid instructors and enhance student comprehension‎.‎ For example‎,‎ chapters align with course modules in both name and number‎,‎ and chapter objectives are stated as questions to encourage students to think about and find answers as they read chapters‎.‎ End‎-of‎-chapter questions and summaries align with chapter objectives to emphasize key topics‎,‎ while key terms are listed in each chapter opener in the order of occurrence to alert students to upcoming vocabulary words‎.‎In addition‎,‎ new features include ‎"‎How To‎"‎ quick references for step‎-by‎-step tasks‎;‎ real‎-world examples and all‎-new illustrations‎;‎ concise explanations with a focus on word usage and sentence structure for improved readability‎;‎ and correlations to the CCNA exam in Chapter Objectives‎,‎ Check Your Understanding questions‎,‎ and new Challenge Activities‎.‎