The best starting point for this book, is to make sure you are on the same page as the exam developers. Having this common vocabulary will reduce confusion in the later chapters. A clear and concise definition of architecture is imperative to your success on this exam. Once you understand the definition, you must understand your role in creating an architecture. You must realize what your tasks are. Finally, you must understand the purpose of creating an architecture. You create an architecture to support the service-level requirements of a system. Without service-level requirements, your systems cannot meet customer demand for availability, reliability, and scalability. It is these service-level requirements that keep a company from having a "CNN" moment, which occurs when the failure of your computer systems makes headline news on CNN.