Computer Networks Chapter 1

Chapter 1 Introduction

Components of a network

                Sender

                Reciever

                Data

                Protocol

                Medium

Communication

                Simplex

                Half-Duplex

                Full-Duplex

Physical network topology (Refer Lecture 2  video of NPTEL  Computer Networks by IIT Kharagpur)

                Mesh

                Star

                Ring

                Bus

Need to understand the advantages and disadvantages of each topology and their applications.

Types of networks

                LAN

                MAN

                WAN

Internet(Evolution)

                ARPANET

                TCP/IP

Protocol and Standards

                Syntax

                Semantics

                Timing

Summary

• Data communications are the transfer of data from one device to another via some form of transmission medium.
•  A data communications system must transmit data to the correct destination in an accurate and timely manner.
• The five components that make up a data communications system are the message, sender, receiver, medium, and protocol.
•  Text, numbers, images, audio, and video are different forms of information.
• Data flow between two devices can occur in one of three ways: simplex, half-duplex, or full-duplex.
•  A network is a set of communication devices connected by media links.
•  In a point-to-point connection, two and only two devices are connected by a dedicated link. In a multipoint connection, three or more devices share a link.
•  Topology refers to the physical or logical arrangement of a network. Devices may be arranged in a mesh, star, bus, or ring topology.
• A network can be categorized as a local area network or a wide area network.
•  A LAN is a data communication system within a building, plant, or campus, or between nearby buildings.
• A WAN is a data communication system spanning states, countries, or the whole world.
• An internet is a network of networks.
•  The Internet is a collection of many separate networks.
• There are local, regional, national, and international Internet service providers.
• A protocol is a set of rules that govern data communication; the key elements of a protocol are syntax, semantics, and timing.
• Standards are necessary to ensure that products from different manufacturers can work together as expected.
• The ISO, ITU-T, ANSI, IEEE, and EIA are some of the organizations involved in standards creation.
• Forums are special-interest groups that quickly evaluate and standardize new technologies.
•  A Request for Comment is an idea or concept that is a precursor to an Internet standard.