Internetworking involves connecting two or more computer networks with some sort of routing device to exchange traffic back and forth, and to guide traffic on the correct path (among several different ones usually available) across the complete network to their destination. Internetworking uses devices called routers (originally called gateways, although that term has fallen into disuse in this context due to confusion with functionally different devices using the same name), and some types of high end switches.
(Some people inaccurately refer to the connecting together of networks with bridges as internetworking, but the resulting system mimics a single subnetwork, and users require no internetworking protocol (such as IP) to traverse it.)
Internetworking started as a way to connect disparate types of networking technology, but it became widespread through the developing need to connect two or more local area networks via some sort of wide area network. The definition now includes the connection of other types of computer networks such as personal area networks.
The most notable example of internetworking in practice has become the Internet, a network of networks running different low-level protocols, unified by an internetworking protocol, the Internet Protocol (IP). IP only provides an unreliable packet service across the Internet; to transfer data streams reliably, applications must utilise a Transport layer protocol (such as TCP). Partly for this reason people commonly refer to TCP and IP together, as "TCP/IP". Some applications occasionally use a simpler Transport layer protocol (called UDP) for tasks which do not require absolutely reliable delivery of data, such as video streaming .
See also
External links
Professor Rahul Banerjee's free e-book on Internetworking Technologies deals with the foundations of major internetworking architectures (chapters 4 to 9).