2.7 Internetwork

Historically, the Internet is a network of independent data networks. These data networks were built by a multitude of different organizations and enterprises whose networks differed in size between LANs and WANs. Besides the differences in size there also existed a diversity in networking technologies. This diversity in technologies is a result of the varying requirements posed by different organisations. For instance, a small company connects its computers with a LAN technology. A large enterprise, on the other hand, interconnects the different sites with WAN technology. Since there exists no networking technology that fits all the needs, a technology that permits the interconnection of multiple heterogeneous networks is required. The scheme that allows the interconnection of different networking technologies is called internetworking.

Animation 2.7-1 shows hows two distant terminals in different LANs (Local Area Networks) communicate with each other.