ct can mean the difference between success and failure. On one hand the protec- tion of a proprietary programming language quickly becomes costly to maintain and an overall burden. On the other hand, non proprietary languages, third party development tools and "free ware" are slowly but surely taking us away from the paradigm of developing applications one line of code at the time, reducing costs and shortening the time to market. All companies do of course have equal access to these same resources, including the pool of engineers that represents the remaining In the context of the 10%-90% discussion above, the question remains "just where is a company's IC vested?" My personal view is that the majority (well over 50%) of a company's intellectual knowledge-based property is vested in the knowl- edge and experience of the less than 10%. In response to this conclusion, this book by Thomas Muth, is the key to opening the door to that 10% critical mass of network knowledge that is crucial for the understanding of present and future architecture of the SO called "Worlds Biggest Machine". Reduce your risk exposure by anchoring your IC with AMLn. Montréal Jens J. Larsen, P.Eng October 2004 Senior Engineer Ericsson Research, Canada Preface Preface This book is about creating and using models as a means to describe and communi- cate the purpose and architecture of network systems faster and more accurate. Today, the architecture of standardized systems is rarely described explicitly. An average protocol or interface specification may comprise several hundreds of pages. For a network system, such as ATM, GSM, ISDN, and others, the number of standard pages produced for its specification easily exceed 3000 pages each. For example, to become an ISDN expert, you have to read (and understand!) over 7000 pages. A complete specification of a network system also comprises a large num- ber of system documents that specify how an implementor intends to realize the standard. Basically, all this information is presented textually, pos