This is a straight update of the 3rd edition of this successful textbook. The aim of the book is to provide a course text for the networking element required by most degree and BTEC Higher National courses in computing. The book covers both the key concepts for understanding local area networks alongside more practical issues such as cabling structures and interconnections of networks. The solid technical content coupled with discussion of the real issues of relevance in practice means the book can be used as a core text to support courses taught through traditional lectures or can be used for self-learning. The book includes both short questions with answers at the end of each chapter and further, longer questions which range in difficulty from the more simple tutorial questions to full examination questions.