Book excerpt: As digital communications networks grow in use and size throughout the world, the need for accurate, reliable test and measurement procedures has increased tremendously. This unique handbook provides the only comprehensive coverage of all the methodologies, data, and reference material necessary to master network instrumentation. In this single encyclopedic resource, engineers will discover how to apply all the test, measurement, and monitoring tools critical to network performance. The success of this richly illustrated handbook is further assured by its authorship--Clyde Coombs is the preeminent editor of electronics handbooks, with a 30 year track record of best sellers.