This textbook aims to inform the reader on all matters relating to computer networks. Present day corporate networks are very complex combinations of hardware and software and in this text I try to provide a brief overview of the components that a networking engineer should understand before proceeding with network infrastructure design. Thus I cover briefly topics relating to general computer hardware architecture and the role of the operating system. Here I deal with areas such as process management and memory management in order to give the reader an idea of the type of workload a computer on a typical network may need to cope with. General background to the technologies that are available for local and wide area networks are provided in order for the reader to be aware of these as options in network specification and design. I have also provided some guidelines to readers regarding the steps involved in the design of network infrastructure.