INTERNET
The Internet, or simply the Net, is the publicly accessible worldwide system of
interconnected computer networks
that transmit data by packet switching using a standardized Internet Protocol (IP). It is made up of thousands of smaller commercial, academic, domestic, and government networks. It carries various information and services, such as electronic mail, online chat, and the interlinked Web pages and other documents of the World Wide Web.
Contrary to some common usage, the Internet and the World Wide Web are not synonymous: the Internet is a collection of
interconnected computer networks, linked by copper wires, fiber-optic cables, etc.; the Web is a collection of interconnected documents, linked by hyperlinks and URLs, and is accessible using the Internet.
there are three layers of protocols:
at the lowest level is IP - the datagram which carries a block of data from one node to another
next comes TCP & UDP - the protocols by which one host exchanges data with another - the former making a virtual circuit giving some level of guarantee of reliability, the latter being a best-effort connection-less transport
on top comes the
application protocol - the specific messages or data stream used by the application running on the hosts to talk to each other.