Internet applications
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Application
Layers
Suite of Internet protocols (TCP/IP)
Other protocols
Internet
Layers
Networks of organizations and service providers
National data communication backbone systems
Network
International data communication backbone systems
Layers
The key Internet protocols are TCP and IP, which stand for Transmission Control Protocol and Internet Protocol. TCP handles the data and splits large messages and data files into smaller packets or 'datagram’s that can be sent easily and independently from one computer to another at the opposite end of internal data communication networks. To each datagram TCP attaches labels, and these are used to reassemble them into the original messages and data files at their final destination. IP creates 'envelopes' around each datagram on which it stamps the addresses of both the computer that sent the message and the one that receive it. Once released, each envelope finds its way to its destination on its own, a process that is t along by the routers, i.e. 'intelligent' computers that contain maps of the network which they use to messages and data files from source to destination. The key idea is that the datagram's travel through the jumble of national and international communication networks independently, and that there actually lasting connection between the two communicating computers.
What do computers communicate and how do they do it?
What do computers actually communicate over the Internet, and how do they do it? Data communication networks are organized to handle digital signals. The files to be transmitted can contain anything the sender wishes to share with other people - plain text messages, formatted documents, data sets, graphics, sound and video — as long as they have been converted to digital form. On the Internet, files are transmitted by means of client-server application software, and there are different client-server applications that share different kinds of data.
