It is believed that the term 'Internet' was coined as an abbreviation of the term Internetworking. Internetworking should be read as 'inter networking' and not 'Internet working'.
Internetworking is a term used to describe the technical process of interconnecting separate computer networks. Internetworking typically uses a device - bridge, router, repeater or a gateway - that uses TCP/IP and routing protocols to connect computer networks that are owned and operated by separate entities.
While the most obvious example of Internetworking is the Internet, Internetworking is a term that can be used to describe the process of interconnecting a variety of computer networks, such as: LANs, PANs or WANs. While Internetworking typically involves the use of TCP/IP, it can also be implemented by the OSI network model. The requirement for Internetworking to be feasible is that the participating networks use the same protocol suite and communication methodology.
Internetworking was pioneered by ARPANET: which connected computer networks through the use of a device named an IMP (a minicomputer and the first router). Each network on ARPANET addressed each packet it created with the address of the destination network: the IMP then used a routing algorithm to send the packet to other IMPs.
In relation to the Internet, as TCP/IP and computers evolved, the process of Internetworking also evolved. Generally speaking, the Internet interconnects networks through the use of gateways and routers that use interior and exterior routing protocols. Some of the most popular interior and exterior routing protocols are: