Page 235 - Informatics_Practices_Fliipbook_Class12
P. 235

Unit III: Introduction to Computer Networks


                       6                                       COMPUTER NETWORKS














              Chapter Outline


              6.1 Components of a Computer Network               6.2 Evolution of Networking
              6.3 Network Topologies                             6.4 Network Types
              6.5 Network Devices






            Friends communicate with each other on social networks, for example,  relatives, classmates, and people in a Facebook
            group form social networks.  A computer network is a collection of interconnected computers in the same spirit. It provides
            a means of communication amongst the computers in a network to share hardware and software resources. The Internet
            is the largest computer network. Computers connected to the Internet can share information amongst themselves. There
            are several applications of computer networks such as collaborative learning, scientific research, video-conferencing,
            online gaming, e-shopping, e-governance, telehealth, and chatting.  This chapter will discuss what constitutes a computer
            network, its categorisations, functionalities, and the technologies that make it work and briefly about the Internet.



                  Computer Networks: Set of devices connected via links.



            6.1 Components of a Computer Network

            The main components of a network are entities participating in the network, the medium through which communication
            takes place, and the content to be communicated. Children in a kindergarten class communicate with the teacher and
            themselves without being aware of any communication support. Of course, we know that communication is made
            possible by the air present in the room that serves as a medium (also called a channel) through which sound waves
            travel from one person to another. In this example, the students and the teacher form the entities, the air is the
            medium, and the conversation in a natural language is the content. Similarly, the computers communicate with each
            other by exchanging (sending and receiving data) the content in the form of binary data. The participating computers
            agree on the norms of communication. Transfer of data between computers (also called nodes or terminals) via some
            channel is called data communication.
            Figure 6.1 shows a communication system comprising the following components:

            •  Sender: The node that sends the data.
            •  Receiver: The node that receives the data.

                                                                                             Computer Networks   221
   230   231   232   233   234   235   236   237   238   239   240