1.0. INTRODUCTION The Internet is a computer global system network. It’s an acronym of International Network. The research on dividing information into packets and switching them from computer to computer began in the 1960s. The U.S. Department of Defense Advanced Research Projects Agency (ARPA) funded a research project that created a packet switching network known as the ARPANET. ARPA focused research on ways that networks could be interconnected, and the Internet was envisioned and created to be an interconnection of networks that use TCP/IP protocols.
Internet, computer-based global information system. TheInternet is composed of many interconnected computernetworks. Each network may link tens, hundreds, or eventhousands of computers, enabling them to share information andprocessing power. The Internet has made it possible for peopleall over the world to communicate with one another effectivelyand inexpensively. Unlike traditional broadcasting media, suchas radio and television, the Internet does not have a centralizeddistribution system. Instead, an individual who has Internetaccess can communicate directly with anyone else on theInternet, post information for general consumption, retrieveinformation, use distant applications and services, or buy andsell products.
2.1.1. INTERNET TOPOLOGYConnecting individual computers to each other creates networks. The Internet is aseries of interconnected networks. Personal computers and workstations are connectedto a Local Area Network (LAN) by either a dial-up connection through a modem andstandard phone line or by being directly wired into the LAN. Other modes of datatransmission that allow for connection to a network include T-1 connections anddedicated lines. Bridges and hubs link multiple networks to each other. Routerstransmit data through networks and determine the best path of transmission.All information is transmitted across the Internet in small units of data called packets.Software on the sending computer divides a large document into many packets fortransmission; software on the receiving computer regroups incoming packets into theoriginal document. Similar to a postcard, each packet has two parts: a packet headerspecifying the computer to which the packet should be delivered, and a packet payloadcontaining the data being sent. The header also specifies how the data in the packetshould be combined with the data in other packets by recording which piece of adocument is contained in the packet.
3.0 CLIENT /SERVER ARCHITECTUREInternet applications are based on the concept of client/server architecture. In aclient/server architecture, some application programs act as information providers(servers), while other application programs act as information receivers (clients).The client/server architecture is not one-to-one. That is, a single client can accessmany different servers, and a single server can be accessed by a number of differentclients. Usually, a user runs a client application, such as a Web browser, thatcontacts one server at a time to obtain information. Because it only needs to accessone server at a time, client software can run on almost any computer, including smallhandheld devices such as personal organizers and cellular telephones
3.1 HOW THE INTERNET WORKS --- Dial –up connection Standard phone line Ethernet - - T1 connection Dedicated lineFig 1.3: How Information travels over the Internet
3.1.1INTERNET ACCESSThe term Internet access refers to the communication between aresidence or a business and an ISP that connects to the Internet. Accessfalls into three broad categories: dedicated, dial-up, and wireless.With dedicated access, a subscriber’s computer remains directlyconnected to the Internet at all times through a permanent, physicalconnection. Most large businesses have high-capacity dedicatedconnections; small businesses or individuals that desire dedicated accesschoose technologies such as digital subscriber line (DSL) or cablemodems, which both use existing wiring to lower cost. A DSL sends dataacross the same wires that telephone service uses, and cable modems usethe same wiring that cable television uses.
Dial-up is the least expensive access technology, but it is also the least convenient.To use dial-up access, a subscriber must have a telephone modem, a device thatconnects a computer to the telephone system and is capable of converting data intosounds and sounds back into data. The user’s ISP provides software that controls themodem. To access the Internet, the user opens the software application, which causesthe dial-up modem to place a telephone call to the ISP. A modem at the ISP answers thecall, and the two modems use audible tones to send data in both directions. When one ofthe modems is given data to send, the modem converts the data from the digital valuesused by computers—numbers stored as a sequence of 1s and 0s—into tones. Thereceiving side converts the tones back into digital values.Wireless network is a kind of computers networks that does not require the use of wiresto connect to the Internet. The connectivity to the Internet with wireless network ismade easy through a wireless router. Wireless networks are categories into; LAN (LocalArea Network), PAN (Personal Area Network) and MAN (Metropolitan Area Network)depending on the use.
4.0. INTERNET APPLICATIONSApart from the World Wide Web that is generally use, some old applications are still used.Telnet application enables a user to interactively access a remote computer. For example,a businessperson who is visiting a location that has Internet access can use Telnet to contacttheir office computer. Doing so is faster and less expensive than using a dial-up modem.Another application, known as the File Transfer Protocol (FTP), is used to download filesfrom an Internet site to a user’s computer. The FTP application is often automaticallyinvoked when a user downloads an updated version of a piece of software. Applicationssuch as FTP have been integrated with the World Wide Web, making them transparent sothat they run automatically without requiring users to open them.Network News discussion groups (newsgroups), is another application, Newsgroupapplication software allows a user to obtain a copy of selected articles from a local newsserver or to use e-mail to post a new message to the newsgroup. The system makesnewsgroup discussions available worldwide.
A service known as Voice Over IP (VoIP) allows individuals andbusinesses to make phone calls over the Internet. Low-costservices (some of them free) often transfer calls via personalcomputers (PCs) equipped with microphones and speakers insteadof the traditional telephone handset.Internet Protocol (IP) is a protocol used for communicating dataacross a packet-switched internetwork using the Internet ProtocolSuite. IP is the primary protocol in the Internet Layer of theInternet Protocol Suite and has the task of delivering distinguishedpackets from the source host to the destination host based on theiraddresses.
5.0. USES OF THE INTERNETOnline Service,provider of electronic news,Information, ande-mail services to customers connecting to the service with theircomputers over modems and telephone lines. Online servicesmay also serve as gateways to other sources of information, suchas bulletin boards, chat groups, and the Internet. Popular onlineservices include CompuServe, the Microsoft Network, andAmerica Online.
5.1. MARKETING AND THE INTERNETThe Internet enable marketers to promote their products and services tomillions of potential customers through the World Wide Web. This Web siteprovides information about a product designed to keep vegetables fresh.
5.3. ELECTRONICS NEWS Electronic News is an online publication that currently covers just the semiconductor production equipment industry. Electronic newspapers spared publishers one of their highest expenses—newsprint—and many brought publishers additional advertising revenue. The New York Times on the Web, an expert of which is shown here, offers readers the same content as its print publication as well as stories and features available only in its online version.
CONCLUSIONThe Internet service has brought a greater development to variouscontinents. It entailed electronic commerce, which the companies used inadvertising, selling, buying, distributing of products, and providingcustomers service. Telecommunication, is the use of e-mail which speedscommunication between the companies, coworkers, and among otherindividuals. File sharing, individuals swap music, movies, photos,applications and enable students to make a research work and downloadmaterials. Online chatting, people carry on discussions using instantmessaging; share digital photo, video, and audio files, also play games inreal time; which cannot be compared to the late years.