(This book is an excellent textbook for network principles and engineering practice. It is not only suitable for teachers to prepare lessons and the organization of curriculum practice, but also conducive to network engineering personnel self-study. The book touches on all aspects of the network, including specifications, protocols, equipment, software configuration, security and system integration, etc., can make you from a layman to an enviable network expert in a short period of time. Arranging content according to learning characteristics is also a major feature of this book. This book provides real-life examples and is equipped with a large number of practical exercises, which not only allow you to easily master the basic principles of networking in a short period of time, but also enable you to learn basic principles. Carry out network practice together in time, so that you become a veritable "theoretician" and "practitioner".)