Software Engineering for Telecommunications Systems
Dominikus Herzberg, Tim Reichert · Wiley Encyclopedia of Computer Science and Engineering · 2008
Abstract Although from today's point of view many commonalities seem to exist between the two, the telephone system and the Internet were historically created with different aims and design philosophies in mind and are based on different technologies. The telephone system was designed primarily for voice communication between humans; even data services like transmission of facsimiles (fax) used tone modulation techniques over the voice channel. The telephone system uses circuit and packet switching to establish a dedicated connection with guaranteed quality of service (QoS) for the duration of a call. The Internet, on the other hand, was designed for flexible data exchange between computers with the capability to compensate single points of failure—it was intended as a network for military purposes in the first place. The Internet uses packet switching for efficient communications with best effort QoS.