This book is intended for the acquisition and development of knowledge and practical skills to build, configure and maintain local computer networks. Concepts and ideas, detailed in the book will provide invaluable information on installing cabling, routing, IP-addressing, routing protocols, and network maintenance. The book covers the basics of model OSI, described in terms such as collisions, network segmentation. The edition includes new chapters on technology and Ethernet switching networks Ethernet. In addition, this tutorial in detail the features of the operating system IOS, TCP / IP protocols, and access control lists.