Internetworking
Internetworking involves connecting two or more distinct
computer networks together into an
internetwork (often shortened to
internet), using
devices called
routers to connect them together, to allow traffic to flow back and forth between them. (Routers were originally called
gateways, but that term was discarded in this context, due to confusion with functionally different devices using the same name.) The routers guide traffic on the correct path (among several different ones usually available) across the complete internetwork to their destination.
(Some people inaccurately refer to the connecting together of networks with
bridges as internetworking, but the resulting system mimics a single
subnetwork, and no internetworking
protocol (such as
IP) is required to traverse it.)
The original term for an internetwork was
catenet. 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 is 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 an internet. To transfer data reliably, applications must utilize a
Transport layer protocol, such as
TCP, which provides a
reliable stream (These terms do not mean that IP is actually unreliable but instead that it sends packets without contacting and establishing a connection with the destination router beforehand. The opposite applies for reliable). Since TCP is the most widely used transport protocol, people commonly refer to TCP and IP together, as "
TCP/IP". Some applications occasionally use a simpler transport protocol (called
UDP) for tasks which do not require absolutely reliable delivery of data, such as
video streaming.
*
History of the Internet*
Active Networking*
E-book (
pdf format) - Deals with the foundations of major internetworking architectures (chapters 4 to 9).
