Data communications and networking / Behrouz A. Forouzan with Sophia Chung Fegan.

We have used the five-layer Internet model as the framework for the text not oniy because a thorough understanding of the model is essential to understanding most current networking theory but aiso because it is based on a structure of interdependencies: Each layer builds upon the layer beneath it and supports the layer above it. In the same way, each concept introduced in our text builds upon the concepts examined in the previous sections. The Internet model was chosen because it is a protocol that is fully implemented. This text is designed for students with littie or no background in telecommunications or data communications. For this reason, we use a bottom-up approach. In this approach, students can learn first about data communications (lower layers) before learning about networking (upper layers). For example, students can learn about signaling, encoding, modulation, and error detection befare learning about data transfer across the Internet. This eliminates the need for two courses: one for data communications and one for networking concepts.