(This book is based on the Ministry of Education's "Higher Industry Education Computer Use and Software Professional Field Technical Shortage Talents Training and Training Guidance Program". This book introduces the basic knowledge of small and medium-sized local area networks, the attributes and selection methods of main network equipment; through examples, it introduces the scheme selection, installation and configuration methods of peer-to-peer network and client/server network formation. Through this book, the reader can master the formation of enterprise network (Intranet) and the configuration of various servers, and understand the engineering method of integrated wiring. This book also introduces the security technology, fault detection and elimination, and upgrade plan of the local area network.)