NETWORKING LESSONS FOR BEGINNERS-INTRODUCTION

Hi,here i begin lessons for networking in a beginners way of approach.I am doing  CCNA certification course right now and I thought it would be beneficial for others if I share what I have learned here. Hope you will find this helpful to learn basics of networking.This introductory chapter is meant to help you understand the importance of communication over networks. We will learn the fundamentals of communications over networks

The world of networks

Introduction

         Communication has evolved greatly. Traditional communication methods such as mail have been overtaken by more sophisticated forms. Electronic Communication methods offer higher speeds; more efficiency, reliability, integrity, security; scale across larger geographical areas and require less resources to use. Tools and services such as e-mail, blogs, podcasts, instant messaging, and social networks among other multimedia methods have changed the way we communicate to a great extent.

In this chapter, we will discuss the following:

1.     The role of networks in our lives

2.     Explain the qualities and elements of a network

3.     Give a brief history of computer networks

The role of networks.

Communication has evolved over the years, from carvings on rocks to more complex forms. Modern communication methods are as a result of the evolution of computer networks. Since the first e-mail was sent back in 1965, communication has come a long way.

 With the internet the world has become more interconnected than ever before. And we are no longer restricted with face to face communication

Computer networks are not just responsible for communication, but our entire way of life has evolved. The way we work, the way we interact, among other ways have changed significantly.

Some of the ways we use computer networks include:

§  Business – online banking, e-mail, e-commerce.

§  Entertainment – online movies, online games.

§  Social interactions – instant messaging, social networking sites.

Clearly, therefore, networks play a central role in our lives.

Elements of a network

§  In order to understand networks we need to understand the elements of a network. There are four main elements that define how communication over networks works.

§  Rules or agreements to govern how the messages are sent, directed, received and interpreted – examples include protocols.

§  The messages or units of information that travel from one device to another – these may be packets, frames among others.

§  A means of interconnecting these devices – a medium that can transport the messages from one device to another – such as copper cables, fibre optic among others.

§  Devices on the network that exchange messages with each other – these may include ip phones, computers, servers, routers among others.

After all these,Some of you might be thinking what defines a perfect network,right?Here it is,

• Fault tolerance and scalability – this means that networks should be able to recover from down time or other faults and should be able to expand as needed.

• Quality of service – this is a measurement instituted in networks so as to ensure that the services provided in a network . For example communication would be poor, if a network had only video and not audio when a business executive is in a video conference call. To ensure quality of service, different services are given different priorities.

• Security – the network should be safe from intrusions from unauthorized access. This would ensure that communication is effective and confidentiality, integrity and availability of information is maintained.

History of computer Networks

·         In the late 1950s, early networks of computers included the military radar system Semi-Automatic Ground Environment (SAGE).

·         In 1959, Anatolii Ivanovich Kitov proposed to the Central Committee of the Communist Party of the Soviet Union a detailed plan for the re-organisation of the control of the Soviet armed forces and of the Soviet economy on the basis of a network of computing centres.^[2]

·         In 1960, the commercial airline reservation system semi-automatic business research environment (SABRE) went online with two connected mainframes.

·         In 1962, J.C.R. Licklider developed a working group he called the "Intergalactic Computer Network", a precursor to the ARPANET, at the Advanced Research Projects Agency (ARPA).

·         In 1964, researchers at Dartmouth College developed the Dartmouth Time Sharing System for distributed users of large computer systems. The same year, at Massachusetts Institute of Technology, a research group supported by General Electric and Bell Labs used a computer to route and manage telephone connections.

·         Throughout the 1960s, Leonard Kleinrock, Paul Baran, and Donald Davies independently developed network systems that used packets to transfer information between computers over a network.

·         In 1965, Thomas Marill and Lawrence G. Roberts created the first wide area network (WAN). This was an immediate precursor to the ARPANET, of which Roberts became program manager.

·         Also in 1965, Western Electric introduced the first widely used telephone switch that implemented true computer control.

·         In 1969, the University of California at Los Angeles, the Stanford Research Institute, the University of California at Santa Barbara, and the University of Utah became connected as the beginning of the ARPANET network using 50 kbit/s circuits.^[3]

·         In 1972, commercial services using X.25 were deployed, and later used as an underlying infrastructure for expanding TCP/IP networks.

·         In 1973, Robert Metcalfe wrote a formal memo at Xerox PARC describing Ethernet, a networking system that was based on the Aloha network, developed in the 1960s by Norman Abramson and colleagues at the University of Hawaii. In July 1976, Robert Metcalfe and David Boggs published their paper "Ethernet: Distributed Packet Switching for Local Computer Networks"^[4] and collaborated on several patents received in 1977 and 1978. In 1979, Robert Metcalfe pursued making Ethernet an open standard.^[5]

·         In 1976, John Murphy of Datapoint Corporation created ARCNET, a token-passing network first used to share storage devices.

·         In 1995, the transmission speed capacity for Ethernet increased from 10 Mbit/s to 100 Mbit/s. By 1998, Ethernet supported transmission speeds of a Gigabit. Subsequently, higher speeds of up to 100 Gbit/s were added (as of 2016). The ability of Ethernet to scale easily (such as quickly adapting to support new fiber optic cable speeds) is a contributing factor to its continued use.