Using a unique modular approach, this cutting-edge introduction to data communications features 11 core chapters of essential material, 6 advanced modules, and a Companion Website to provide the widest possible range of topics around which to customize courses with specific goals. This approach allows selective emphasis without requiring instructors to assemble their own additional material. Plus, 9 mini-chapters for hands-on material and case studies give students a feel for what they will encounter on the job.