Introduction to internet
- 2. 1.0 INTRODUCTION • The development of micro computers and merging of computers and communications has profound influence on the way computer systems are organized. The old model of isolated computers serving the needs of organizations has been replaced by large number of separate but inter connected computers known as computer networks. The connection between two computers can be copper wire, fiber optic cable , microwaves or communication satellite. The use of computer networks was the result of US Defence Project ARPANET (Advanced Research Project Agency NETwork) initiated around 30 years back to develop computer network connecting a few computers of universities and research organizations in USA for data transfer between computers.
- 3. • The computer networks have many uses, One of the primary use is making available all programs, data and equipment to any one on the network irrespective of physical location of the users. In other words a user who is 1000 km away can access data on remote computer as though it was local. Thus we can say that Internet is a network of tens of thousands of computer networks. Every network and every computer on these networks exchange information according to certain rules called Protocols. Two computers working with different operating system can communicate because of the same Protocol. Two protocols used for working with the Internet are Internet Protocols or IP and Transmission Control Protocol or TCP.
- 4. • We can often see these mentioned together as TCP/IP when references are made to the software needed to make an Internet connection. Each network and computer system on the Internet has an Internet address called an IP address. The address is used to exchange information, and, or receive e-mail, etc
- 5. 1.1 USES OF NETWORK • Computer networks provide high reliability by making available alternate sources for supply. For example, the programs and data can be replicated on two or more machines so that if any one of the machines is not available, the other copies can be utilized. Similarly the presence of multiple computers on the network enables even if one of the systems breaks down, the other can be able to take over the work failed ones. • Another use of computer networks is saving money. Small computers have much better performance compared to their price. The larger computers (Main frames) may be 10 times faster than smaller ones but the cost is 1000 times more than smaller computers.
- 6. • This imbalance made many system builders to go for a ne for a network of smaller components. We can add more and more ne computers to the network whenever work load increases. Hence computer network is easily expendable. • Very important usage of computer network is communicate media. With the network, it is easy for two or more people who live far apart work together. The collection of interconnected networks is called inter-network or internet. The specific inter-network, which uses TCP/IP is the INTRANET not the INTERNET.
- 7. 1.3 WHO GOVERNS THE INTERNET ? • There are no single organisation who owns the Internet, there are number of volunteer organisations which are responsible for different types of activities such as : • IAB - THE INTERNET ARCHITECTURE BOARD, which is responsible for approving standards and allocating resources. • IETF - THE INTERNET ENGINEERING TASK FORCE , which is responsible for discussing and investigating the technical problems on the Internet. • InterNIC - This organization is responsible for providing registration services to Internet users.
- 8. 1.4 REQUIREMENTS Internet Connection Modem Telephone Line Program which control the communication of data over the hardware component.
- 9. ISP (INTERNET SERVICE PROVIDER) • An Internet service provider (ISP) is an organization that provides services for accessing, using, the Internet. Internet service providers may be organized in various forms, such as commercial, community- owned, non-profit, or otherwise privately owned. • Internet services typically provided by ISPs include Internet access, Internet transit, domain name registration, web hosting, Usenet service, and colocation.
- 10. MODEM • A modem is a computer peripheral that allows you to connect and communicate with other computers via telephone line, it stands for MOdulator – DEModulator . • Modem come in different speeds and is measured in bps or bits per second. 28.8 Kbps modem transmits data up to 28,000 bits per second. A 56 Kbps modem is twice as fast, sending and receiving data up to 56,000 bits per second. Almost all modem today are 56 Kbps. • Integrated Services Digital Network (ISDN) is a line by which data is transmitted over digital telephones lines. ISDN is two to four times faster than modems. Use of ISDN lines on Internet’s World Wide Web helps transmit or receive text , graphics, sound and videos. Many ISP’s provide these ISDN lines.
- 11. There are two types of modems : Internal Modem: An internal modem slips into an expansion slot provided in the computer. The phone cord is plugged into a jack, through the back of the computer. It is less expensive than external modem. External Modem: An external modem is placed outside the computer. This modem is connected to the computer through USB cable or through serial cable and the telephone is connected to the modem, thus providing computer access to the outside world.
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