Network Management 16.12 Management of Layered and Serial Interworking 16.13 Conclusions Appendix 1 Web Services and a Service-Oriented Architecture Appendix 2 Financial Calculations Appendix 3 Development Tracks Appendix 4 Dimensioning Media Gateways and Associated Telephony Servers Index Preface Many readers can use this book as a 'standalone'. For other readers it might favorably be combined with a 'conventional' book/other learning material covering the particu- lar technical area of the reader. This would create an excellent combination of depth and breadth. The chosen broad context-oriented approach does not only require a number of books, articles, standards, etc. as input. In fact, finding a suitable book structure has been the most demanding issue. For the main author it has taken years to acquire a reasonable conviction. Often, the evolving conviction tends to successively upgrade business aspects on behalf of technology, in order to justify the title word 'Understanding'. Understanding is also firmly related to a pronounced pedagogical goal of the book. Finding a good book structure for a broad subject is similar to building a house with a number of rooms for different purposes. Filling the chapters with content then corresponds to furnishing the rooms. Changing the rooms is difficult and expensive. Changing the furnishing is easier and mistakes can more easily be corrected. New modern furniture can replace older inventories. To make the structure issue even trickier, the telecom complexity of today requires different types of 'rooms': Functional rooms devoted to a specific purpose, such as security or quality of service. More hardware and implementation oriented rooms, such as access and control equip- ment and its capabilities. Process flow oriented rooms, where we can identify the users, the various service providers (in a broad sense) and their planning, implementation and management, the technical development tracks and the related business models. The main references mentioned in the reference se