ant it, and order it. Once that's done, it must be delivered. Content transport simply delivers the valuable property. Somewhere in the process, money or other good and valuable property passes in the opposite direction. THE PROGRAM CONTENT FOOD CHAIN The program content food chain envisions three distinct stages: cre- ation, distribution, and delivery. Each stage is unique. Designing and building networks to transport the content within and between each of the stages must address the unique nature and quality characteris- tics of digitized content. For reasons presented later, the nature of the content is quite different in each of the three stages. It's not a "one size fits all" world anymore. The days of one analog program on one analog transmission channel are numbered. The program content food chain model illustrates the flow of content from start to finish. The path of travel for content was initially, and 1 BASIC FUNDAMENTALS, DEFINITIONS, AND KEY TERMS still is in large part, made up of analog vehicles. Moving content in this kind of environment is very limited, and subject to noise, distor- tion, and deterioration found in passive conductor and radio wave transmission facilities. Initially and for many years, the life cycle of content was very short. Essentially limited to real-time or live ses- sions only, the invention of recording and playback schemes enabled multiple use of content. This basic capability enabled non-real-time content transport by physically moving the media it was stored on. For the purposes of this book, we will focus on network media, not storage. Gradually, content production equipment and systems have mi- grated from analog to digital technology, driven in large part by less expensive electronic components developed for the computer and telecom industries. In fact complete, all digital, end-to-end paths are possible with cable modems, terrestrial, and satellite trans- mission facilities. Figure 1-1 is an illustration of the three stages of the life cycle of program content. It al