Digital Data Communication

Although the technology enabling Data Communication evolves at a vertiginous speed, the principles behind this restless field are basically like what they were a decade ago. This explains why in this book – meant for an undergraduate introduction course to computer networks – the classic 7-layer ISO Reference Model still rules! This model may have been categorized by some as "purely academic", but nevertheless it is a very potent pedagogical approach to the subject. Regardless, although TCP/IP has been adopted as the de-facto standard by the industry, the ISO model is making a slow but certain return. Starting from the very basics, information transmission is explained step-by-step. The first chapter deals with communication models, architecture and protocols. The ISO Reference Model is intuitively introduce as an elegant solution to separate a set of complex activities into manageable task chunks. Concepts of noise, attenuation and delay are introduced to highlights the limitations of communication channels. To ensure that the practical aspects of these concepts are well understood, wired and wireless medias are introduced before dealing with data encoding. The delicate topics of synchronization at the bit, character and frame level as well as interfacing are introduced. The very popular based protocol (HDLC) is presented as an efficient means to elegantly deal with flow and error control. Multiplexing in the time, frequency and code domain are presented and their natural extension namely circuit and packet switching are discussed in the last section of the book.