A Computer Network, often simply referred to as a network, is a collection of hardware components and computers interconnected by communication channels that allow sharing of resources and information and it is just a part of our daily life. This text book has been developed in a systematic manner which is based on the prescribed syllabus of Rajasthan Technical University, Kota for B.Tech VIII semester (EC) students. Authors: Er. Amit Rao, Archana Soni.