data

…is commonly referred to as data, and its analog counterpart is called source data. Vast quantities of nondocument analog data are collected, digitized, and compressed automatically by means of appropriate instruments in fields such as astronomy, environmental monitoring, scientific experimentation and modeling, and national security. The capture of information generated…

…timely and correct transfer of data, and the top four ensure that arriving data are recognizable and useful. While all seven layers are usually necessary at each user location, only the bottom three are normally employed at a network node, since nodes are concerned only with timely and correct data…