The Internet is a worldwide, publicly accessible series of interconnected computer networks that transmit data by packet switching using the standard internet protocol (IP). It is a "network of networks" that consists of millions of smaller domestic, academic, business, and government networks, which together carry various information and services, such as electronic mail,online chat,file transfer, and the interlinked web pages and other resources of the World Wide Web(WWW).
History Sputnik United States to create the Advanced Research Projects Agency, known as ARPA, in 1958 British Post Office, Telenet, DATAPAC and TRANSPAC collaborated in 1981 TCP/IP in 1983 1985 NSF commissioned 56kb/sec n/w backbone using Fuzzballs followed by commission of 1.5 megabit/second backbone called NSFnet 1988 opening the network for commercial interest.The US Federal Networking Council approved the interconnection of the NSFNET to the commercial MCI Mail system in that year and the link was made in the summer of 1989. Other commercial electronic e-mail services were soon connected, including OnTyme, Telemail and Compuserve. In that same year, three commercial Internet Service Providers were created: UUNET, PSINET,CERFNET
Important, separate networks that offered gateways into, then later merged with, the Internet include Usenet and Bitnet Various other commercial and educational networks, such as Telenet, Tymnet Compuserve and JANET were interconnected with the growing Internet. Telenet (later called Sprintnet) was a large privately funded national computer network with free dial up access in cities throughout the U.S. that had been in operation since the 1970s. This network was eventually interconnected with the others in the 1980s as the TCP/IP protocol became increasingly popular The ability of TCP/IP to work over virtually any pre-existing communication networks allowed for a great ease of growth,
GROWTH World Wide Web project. The Web was invented by English scientist Tim Berners-Lee in 1989 An early popular web browser was ViolaWWW, based upon HyperCard. It was eventually replaced in popularity by the Mosaic web browser. In 1993, theNational Center for Supercomputing Applications at the University of Illinois released version 1.0 of Mosaic, and by late 1994 there was growing public interest in the previously academic, technical Internet. By 1996 usage of the word Internet had become commonplace, and consequently, so had its misuse as a reference to the World Wide Web Meanwhile, over the course of the decade, the Internet successfully accommodated the majority of previously existing public computer networks (although some networks, such as FidoNet, have remained separate). During the 1990s, it was estimated that the Internet grew by 100% per year, with a brief period of explosive growth in 1996 and 1997
Todays Internet Aside from the complex physical connections that make up its infrastructure, the Internet is facilitated by bi- or multi-lateral commercial contracts (e.g., peering agreements), and by technical specifications or protocols that describe how to exchange data over the network. Indeed, the Internet is essentially defined by its interconnections and routing policies. Review, philosopher N.J. Slabbert, a writer on policy issues for the Washington,D.C. –based Urban Land Institute, has asserted that the Internet is fast becoming a basic feature of global civilization, so that what has traditionally been called “civil society” is now becoming identical with information technology society as defined by Internet use.
Summary of Stages in development of internet Innovation (1961-1974) The concept of packet switiching The first “killer app”of internet is born Invention of client server computing TCP/IP is invented Instituitionalization (1975- 1995) TCP/IP adopted as DoD standard Personal computers invented Domain Name server introduced (DNS ) www is born NSFNET created Commercialization(1995 onwards) Fully commercial internet is born. Netwoks as AT&T,Sprint,UUNet,MCI take over operations of backbone Ecommerce begins with pur online retail stores and auctions
WWW The World Wide Web (commonly shortened to the Web) is a system of interlinked hyertext documents accessed via the internet. With a Web browser, a user views Web pages that may contain text, images,videos, and other multimedia and navigates between them using hyperlinks. The World Wide Web was created in 1989 by Sir Tim Berners- Lee, working at CERNin Geneva, Switzerland. Since then, Berners-Lee has played an active role in guiding the development of Web standards (such as the markup languages in which Web pages are composed), and in recent years has advocated his vision of a Semantic web. Robert Cailliau, also at CERN, was an early evangelist for the project.
Working of WWW Typing of URL in web browser or using hyperlink Resolving of IP address Using DNS HTTP request sent to the web server,html page requested first ,parsed and then additional req is sent for images and other files. browser then renders the page onto the screen as specified by its HTML, CSS and other Web languages. Any images and other resources are incorporated to produce the on-screen Web page that the user sees.
Different internet access methodsACCESS METHOD MAXIMUM DATA RATETelephone modem 56kbpsEthernet (local area n/w) 10/100mbpsISDN 112-128 KBPSCable modem 30 Mbps (theoretical) 1.5 Mbps(practical)Asymmetric digital subscriber line 1.5-9Mbps(network to users)(ASDL) 16-640kbps(users to network)Wireless local area network 1-2 Mbps
Internet service provider ISP An Internet service provider (abbr. ISP, also called Internet access provider or IAP) is a business or organization that provides consumers or businesses access to the internet and related services. I In the past, most ISPs were run by the phone companies. Now, ISPs can be started by just about any individual or group with sufficient money and expertise. In addition to Internet access via various technologies such as dial-up and DSL, they may provide a combination of services including Internet, domain name registration and hosting, web hosting etc
Internet Governing Bodies IAB-Internet Architecture Board ICANN –Internet Corporation for assigned name and numbers IEGS-Internet Engineering Steering group IETF-Internet Engineering task force W3C-World Wide Web consortium
Governing Bodies in India IAMAI- Internet and mobile Association of India ISPAI- Internet service provider Association of India IOAI –Internet and online Association of India
NETWORK TOPOLOGYIn computer networking, topology refers to thelayout of connected devices
Bus networks use a common backbone to connect all devices. A single cable, the backbone functions as a shared communication medium that devices attach or tap into with an interface connector. A device wanting to communicate with another device on the network sends a broadcast message onto the wire that all other devices see, but only the intended recipient actually accepts and processes the message. Ethernet bus topologies are relatively easy to install and dont require much cabling compared to the alternatives. 10Base-2 ("ThinNet") and 10Base-5 ("ThickNet") both were popular Ethernet cabling options many years ago for bus topologies. However, bus networks work best with a limited number of devices. If more than a few dozen computers are added to a network bus, performance problems will likely result. In addition, if the backbone cable fails, the entire network effectively becomes unusable.
Ring In a ring network, every device has exactly two neighbors for ] communication purposes. All messages travel through a ring in the same direction (either "clockwise" or "counterclockwise"). A failure in any cable or device breaks the loop and can take down the entire network. To implement a ring network, one typically uses FDDI, SONET, or Token Ring technology. Ring topologies are found in some office buildings or school campuses.
Star Many home networks use the star topology. A star network features a central connection point called a "hub node" that may be a network hub, switch or router. Devices typically connect to the hub with Unshielded Twisted Pair (UTP) Ethernet. Compared to the bus topology, a star network generally requires more cable, but a failure in any star network cable will only take down one computers network access and not the entire LAN. (If the hub fails, however, the entire network also fails.)
Tree Tree topologies integrate multiple star topologies together onto a bus. In its simplest form, only hub devices connect directly to the tree bus, and each hub functions as the root of a tree of devices. This bus/star hybrid approach supports future expandability of the network much better than a bus (limited in the number of devices due to the broadcast traffic it generates) or a star (limited by the number of hub connection points) alone.
Mesh Mesh topologies involve the concept of routes. Unlike each of the previous topologies, messages sent on a mesh network can take any of several possible paths from source to destination. Some WANs, most notably the Internet, employ mesh routing. A mesh network in which every device connects to every other is called a full mesh. As shown in the illustration below, partial mesh networks also exist in which some devices connect only indirectly to others.