Chapter 2
Data Transmission
Data transmission plays an important role in wireless broadband networks, and understanding this process is crucial to correctly dimension the network. The bulk of the data traffic handled by the networks will be the Internet, using TCP/IP protocol. Besides, all interconnections to the wireless system will come from wired networks, where the Ethernet prevails.
2.1 History of the Internet
In the late 1960s, it became obvious that there was a need to interconnect computers. In 1970, the ISO (International Standards Organization) developed a reference model called OSI (Open System Interconnection), which defined a seven layers model. This model became the reference for comparing different protocols, but its full implementation was extensive and was not practical for the majority of the applications. This model was defined by a committee and lacked practical implementations. OSI-defined protocols were then developed by several entities such as the ITU-R (CCITT) X.25 for packet switching and EISA/TIA-232 and 422. Large computer manufacturers implemented proprietary OSI-based protocols such as SNA (System Network Architecture) from IBM or DSA (Distributed System Architecture) from Honeywell Bull and others.
In the USA, the first attempts to interconnect different computer platforms at different locations were sponsored by DARPA (the Defense Advanced Research Projects Agency) through the implementation of the ARPANET (Advanced Research Projects Agency Network) ...
