Note that while the OSI Reference Model is useful for discussing networking concepts, many networking protocols do not closely follow the OSI model. Each layer in the OSI model communicates with the corresponding layer on the remote machine as shown in the OSI Reference Model figure . The layers pass data only to the layers immediately above and below. Individual users as well as organizations use networks for many reasons. Data queries entail searching data files for specified information.
Data updating involves altering, adding, or deleting data stored in local or remote files.
Remote batch entry consists of entering batches of data from a remote location, an activity often performed at night or during periods of low system usage. Because of such diverse capabilities, communications and networks are not only desirable but necessary. Sharing resources is another function of networks. A communications network also provides a means for users to communicate using electronic mail.