Over the past decade, global computer and information networks – a unique symbiosis of computers and communications-have been increasingly developed. All countries are actively joining global networks. More than 30 million people use the world system of computer communications every day. The need for means of structuring, accumulation, storage, search and transmission of information is increasing. These needs are met by information networks and their resources. The joint use of network resources (software libraries, databases, computing power) is provided by the technological complex and means of access.
Wide area network (WideArea Network, WAN) is a telecommunication structure connecting the local network with a common communication Protocol, connection methods and communication protocols. Each of the global networks (INTERNET, BITNET, DECNET, etc.) was organized for specific purposes, and further expanded by connecting local networks that use its services and resources.
The largest global information network is the Internet. The Internet is a global global network of information exchange, which brings together several million people from more than 100 countries with the help of modern and convenient means of communication. The Internet began its existence in 1969.
The architecture of the Internet network is developed on the basis of the concept of interconnection or interconnection of heterogeneous networks built on the basis of different physical communication systems and communication technologies.
Thus, the Internet is a set of technical tools, standards and arrangements that allows you to maintain communication between different computer networks in the world.
The basis of the functioning of the Internet is the basic Protocol TCP/IP
(TransmissionControlProtocol/InternetProtocol). It is a set of protocols – systems of standards and rules of communication and information transfer in the global network. A Protocol is an agreement about the signals that computers exchange when they communicate with each other and receive or transmit information.
Service providers are institutions that provide commercial Internet connection services (Internet service provider, ISP) to individual and collective users. In service provider organizations, Internet servers are a computer or program that provides services to other computers or programs.
A client is a computer or program that uses Internet server resources. As a rule, several client programs work simultaneously on the Internet user’s computer (for example, programs for working with e-mail, a browser program for viewing hypertext Web-documents, and the like). Most Internet users work on regular personal computers. The number of Internet services available to them depends on the type of connection to the network.
There are several types of connection to the Internet:
1. On-line (“live”) – the user’s message with the remote computer in real time. On-line modes:
a) temporary IP connection;
b) permanent IP connection;
C) temporary (session) terminal accesses on-line;
2. Off-line (offline or offline) – the work of the PC user before the start of a session with another computer on the Internet. Off-line mode is a session connection with the transfer of mail over the UUCP Protocol.
Internet – based services are systems that provide services to Internet users. These include: email, WWW, newsgroups, lists of rossiki, FTP, IRC, and other products that use the Internet as transmission media of information.
Services provided by the Internet can be divided into two main categories:
1. Deferred (off – line) – the main feature of this group is the presence of a temporary break between the request and receipt of information.
2. Direct (on – line) – differ in that the information on request is returned immediately. If the recipient of the information is required to respond immediately to it, such a service is interactive.