A computer network is defined as a digital communications network which allows sharing of information and resources between nodes. The network between these nodes could be either wired, optical, wireless or a combination of them. The nodes could include a variety of devices such as servers, personal computers, networking hardware, etc. Depending upon the size of the networks or the number of devices connected, they can be classified into four categories, namely, personal area network (PAN), local area network (LAN), metropolitan area network (MAN) and wide area network (WAN). They can also be classified on the basis of the layout arrangements into bus, star, ring, mesh and tree topology. Computer networks have many applications such as access to World Wide Web, instant messaging, e-mail and shared use of devices like fax machines, printers, storage servers, etc. The topics included in this book on computer networking are of utmost significance and bound to provide incredible insights to readers. It explores all the important aspects of computer networking in the present day scenario. Those in search of information to further their knowledge will be greatly assisted by this book.