This book explains how CallManager (originally developed by Celsius Systems) goes about providing call-control services to IP telephony devices and perform reliably as a corporate telephone switch, and offers insights on how the product can be developed. The volume provides systems architects, engineers, and technicians with the details of implementation they need to build strong CallManager systems. Written by members of the CallManager development team and extensively edited for accuracy, Cisco CallManager Fundamentals uses prose and network diagrams are very clear to make his points. While technicians looking for click, click-that procedures will be generally disappointed (such didactic techniques are not typical of the Cisco Press books), they will find quite a lot of sections that explain, in general, how to do administrative work such as loading the username 'into the CallManager database and routing calls to emergency numbers. Does not include details of CallManager integration with the Intelligent Contact Manager (ICM) business-rules engine, or a lot of external information (CTI) Computer Telephony Integration applications.