Unit 9 “Internet”

I. Read and translate the following international words:

Сommunication; segment; to form; commercial firms; company; administrative organization; to control; structure; system; protocol; credit card companies; global; automatic; final; formatted documents; original; addressee.

II. Read the text “Internet” (1) and find English equivalents for the following Russian words and word combinations:

Большое количество маршрутизаторов; изменить всю систему; требовать; действовать одновременно; сетевые протоколы; цифровые сигналы; датаграмма; удалённый компьютер; простые текстовые сообщения.

Internet (1)

Computers, switches, routers, wires and satellites. We often talk about the Internet as if it is only hardware - large numbers of computers, switches, routers, wires and satellite data communication links. Indeed, the Internet consists of various national and international data communication backbone segments, which form the high-speed core of the network, and many sub-networks connecting offices and workers within international, governmental and governmental organizations, educational and research institutions and a rapidly growing number of commercial firms; online service providers such as and Internet service providers (ISPs) and through them large numbers of small companies and individuals. A salient feature is that no 'central' organization 'runs' this hotchpotch of networks. Of course, there are administrative organizations that control regional and national backbone segments, and others that handle the registration of unique names for individual websites. However, all these administrative structures loosely organized, and there is no central control. What is more, new sub-networks can be added without having to reconfigure the whole system.

Key Internet Protocols: ТСР/IР. Every form of communication — whether between people or between computers — requires protocols to support it. Within the Internet, dozens of such protocols operate simultaneously. The strength of the Internet protocol suite is that it can be placed on the top of wide variety of communication networks which are operated on the basis of different network protocols. It should be noted here that the suite of Internet protocols is not the only one that is being used. For instance, public telecom operators, banks and credit card companies use different suites of protocols to operate the global network of automatic teller machines while using the data communication cable networks.

The Internet: layered communication architecture

Internet applications

Email Mailing lists Newsgroups FTP WWW

Application

Layers

I

Suite of Internet protocols (TCP/IP)

Other protocols

nternet

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.