"Welcome to the sixth edition of Data Communications and Networking with TCP/ IP Protocol Suite. We are living in an information age, and information is distributed faster that ever using the Internet, which works based on the topics discussed in this book. Features Although the main goal of this book is to teach the principles of networking, it is designed to teach these principles using the following features: TCP/IP Protocol Suite This book is designed to teach the principles of networking by using the TCP/IP protocol suite. Teaching these principles using protocol layering is beneficial because these principles are repeated and better understood in relation to each layer. For example, addressing is an issue that is applied to several layers of the TCP/IP protocol suite. Another example is framing and packetizing, which is repeated in several layers, but each layer treats the principle differently. Bottom-Up Approach This book uses a bottom-up approach. Each layer in the TCP/IP protocol suite is built on the services provided by the layer below. We learn how bits are moving at the physical layer (first layer) before learning how some programs exchange messages at the application layer (fifth layer). Organization The book is made up of 13 chapters, six appendices, a list of references, and a glossary. Chapter 1: Introduction This chapter is an introduction to Data Communications and Networking with TCP/IP Protocol Suite. It defines the concept of protocol layering and gives a brief description of the TCP/IP protocol suite and the OSI model. Chapter 2: Physical Layer This chapter describes the first layer of the TCP/IP protocol suite: the physical layer. It explains the relationship between data and signals and describes both analog and digital signals. It also discusses multiplexing to benefit from the available bandwidth. Finally, it goes below the physical layer and discusses the transmission media"--