From years the seventies that issue of global village with the unveiling the global TV, found out the scientific and more tangible aspects to previous theories and since many of the behaviors and economic events, social and cultural global society was formed within media groups issues. Nuclear world, the world of IT, the world of nanotechnology and etc, gave replaced by the concept of dominance that the era of "communication" has been known. Age of Communication is the name that set the right on period of time that is axis of all the sciences, technology, politics and society of communication and it show off the area of media dominations above all political power, military and technological. Computer network is nothing more than a tool in the service of knowledge but this tools are needed the things that the human mind to collect data, test and results, it achieved in the shortest possible time. It made easy and quick access to information and using the processing power of strong and efficient computers and applying the communication modern technology to exchange information and to make the intelligent software has led to the flourishing of all branches of science. The purpose of this book is the wide and applicable studying on different dimensions of computer networks. The book includes four chapters, in the first chapter of this book we deals with definitions, learn the basics and fundamental concepts of computer networks. In second chapter, are discussed to study the different dimension of computer network management. In third chapter, have been investigated to study the important issue of security and protection of computer networks and in the fourth chapter of this book, has been studied the topics of WiMAX and wireless networks. All attempts were that in addition to focusing on basic and theory concepts, the applicable and practical concepts are also presented among the topics.