Configuring CallManager and Unity: A Step-by-Step Guide
Reviewer Name: Fouzan M. Pal, Senior Network Security Engineer
Reviewer Certification: CCNA
Configuring CallManager and Unity: A Step-by-Step Guide by David Bateman is perhaps the best book currently out there on this subject. It is over 500 pages and has all the elements of an indispensable book: easy to read, practical in its approach, well organized, and packed with current, useful, and up-to-date information. If you are involved in configuring or maintaining the Cisco CallManager suite of VoIP telephony, you simply cannot do without this book.
As those of us who have been involved with configuring or maintaining the CallManager and Unity system, it is not a trivial task by any means. (I decided to grab this book as a result of an already operational CallManager system that I inherited. I needed get my hands on a practical book that wouldn’t take me for a fluff-ride.) There are a number of interconnected details that need to be worked out. While one can try their luck and make their way through them by accepting defaults settings etc., in order to attain an optimal system that can grow to an enterprise level without resulting in frustrating performance and/or security problems, a somewhat detailed understanding of the system and the parameters associated with it is essential. This book does an excellent job of walking the reader through the configuration of these parameters and providing just the right explanation of the concepts behind them. For example, the author, seemingly well aware of the elements of good technical writing, uses the same type of wording when describing similar concepts. This is a key element of a good technical book since the subject matter of such books can get complicated and it is a good practice to use the same type of wording and similar structure to emphasize the similarity in the topics being covered. The author has used this and other techniques to his advantage when writing this book.
The book is divided into two major sections: one dealing with the CallManager and the other dealing with Unity. Both sections are very well written and references are made to the necessary parts within the sections to emphasize the relationships whenever necessary. Another very important point is that the author has presented the material in the book in generally the same order as one would configure the system. The material is further combined under the same logical groupings as found in the actual application. For a complicated system like the CallManager, this goes a long way in understanding how things tie together in the application and hence helps in getting the "big picture," as well as the details.
As far as suggestions and recommendations go for the author, I would love to see the author write a book on the design of CallManager networks. Just like a good design is critical to the performance of data networks, VoIP networks do not scale well unless backed by a robust design. In fact, performance in voice networks is even more important due to the time sensitive nature of the traffic being carried. A book on the design aspects of VoIP networks would be most welcome. Similarly, installation of CallManager is not covered in this book since that topic can easily take up a book itself. While CallManager installation is usually performed by Cisco itself, a book on this topic would be nice as well.
The need for this book is best described in the words of the author. He writes in the introduction: "While there are many fine Cisco Press books on this technology, I noticed many of my students requesting a task-oriented book... Through the writing process, the book evolved from offering only a step-by-step guide into also offering easy to understand explanations for many of the Cisco IP Telephony concepts and components." While many authors make grand claims about their books, this one holds true to every word of it. The book does exactly as the author claims: it not only presents a very detailed step-by-step approach to configuring the Cisco VoIP solution (which is no doubt a complex and intricate system) but also presents much needed explanations of the steps in a clear, concise manner whenever necessary.