A Companion Guide (CG) is the full-featured textbook that supports a Cisco Networking Academy course. The chapter content aligns 1:1 to the online course topics, but not necessarily word-for-word. The features of the textbook are designed to reinforce the course material and enhance student comprehension and retention of the course topics. As a portable learning tool, the CG is intended to help students focus on important concepts, organise their study time for quizzes and exams, and serve as a future reference resource. The CG serves as an additional instructional tool for the instructor to assign take-home reading or vocabulary homework to better prepare the students for in-class lab work and discussions.