Page 107 - Web Applications (803) Class 11
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BASICS OF NETWORKING AND                                                     1


                                        WEB ARCHITECTURE





                 As we know, social media websites and apps are the platforms that allow us to communicate with each
                 other through video call, message chat, voice call, etc. at any time and from anywhere. These websites
                 and apps provide such facilities to us with the help of a global computer network. A computer network is a
                 collection of interconnected computers that can communicate with each other through a communication
                 medium. A communication medium is a way through which data can be transferred from one computer to
                 another. It can be wired or wireless. The Internet is the world’s largest computer network.
                 In this unit, you will learn about the evolution of the Internet and its different terminologies. Next, you
                 will learn about different types of networks and protocols. Then, you will learn about different types of
                 network architecture. Further, you will learn about the web server and the web client. At the end of this
                 unit, you will learn about network threats and security measures.

                   1.1 THE INTERNET
                 The Internet is a worldwide network made up of numerous independently operated networks. It does
                 not have a centralised governing body. Internet Service Providers (ISPs) are a group of government and
                 private organizations that work together to provide Internet connectivity. The Internet allowed people to
                 share information and connect with each other over long distances. The maximum data transfer rate of a
                 network or Internet connection is referred to as bandwidth.

                 Evolution of Internet
                 Nowadays, we hardly think twice before logging onto the Internet and posting comments on Instagram or
                 Twitter. However, such instant communication was not possible many years ago. Smoke signals and pigeons
                 were used to send messages. Over the years, the need for instant and secure communication has led to
                 tremendous growth. The following diagram shows the evolution of the Internet:


                                            During the Cold War, the
                                           US Department of Defense
                                           (DoD) recognized the need to
                                           build fault-tolerant networks
                                          that would not fail in the event   The United States
                      It was in 1876 that   of a nuclear attack and could   Department of Defense saw
                     Alexander Graham Bell   withstand a single point of   the need to link different
                     proposed the idea of   failure. Digital packet switching,            TCP/IP (Transmission Control
                  communication via telephone   which divides the message to   geographic research   Protocol/Internet Protocol)
                   lines. This led to the creation   be conveyed into little portions   computers to build a   was created in 1970 for
                     of the Public Switched   called packets, was proposed by   network. As a result, in 1969,   communication between
                   Telephone Network (PSTN)   Paul Baran, Donald Davies, and   the Advanced Research   multiple heterogeneous
                     in 1877. It ushered in   Len Kleinrock. Packet switching   Projects Agency (ARPA) of   networks. Along with many
                    new horizons by allowing                        the Pentagon created a   smaller networks, the National
                   people to communicate via   is based on link sharing, as   computer network named   Science Foundation (NSF) of
                   telephone lines. From that   opposed to circuit switching,   ARPANET. ARPANET made use   the United States created
                     time, communication    which reserves resources along   of digital packet switching
                      was mainly through    a dedicated communication   technologies.     NSFNET in 1984 for research
                       telephone lines.           line.                                     and teaching purposes.




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