This book is now in its sixth edition in its forty-year journey. Each edition corresponded to a different phase in the use of computer networks. When the first edition appeared in 1980, networks were simply an academic curiosity. Now, in the sixth edition, the industry's focus is on high performance, with 5G mobile networks, Ethernet 100 gigabit, and 802.11ax WiFi at speeds up to 11 Gbps readily available.

The book has undergone significant additions and modifications to be fully updated with the new trends and capabilities in technology and the security of computer networks. In addition, dozens of new exercises and dozens of new bibliographic references have been added.