Computer Network Assignment A134738 & A134422

INTRODUCTION
A network is a group of computers and devices interconnected by communications channels that facilitate communications among users and allows users to share resources. Networks may be classified according to a wide variety of characteristics.

BACKGROUND
The Internet grew out of an experiment begun in the 1960s by the U.S. Department of Defense. The DoD wanted to create a computer network that would continue to function in the event of a disaster, such as a nuclear war. If part of the network was damaged or destroyed, the rest of the system still had to function. That network was called ARPANET(Advanced Research Projects Agency Network) which linked U.S. scientific and academic researchers, the forerunner of today's Internet. Before the advent of computer networks that were based upon some type of telecommunication system, communication between calculation machines and early computers was performed by human users by carrying instructions between them. Many of the social behaviors seen in today's Internet were demonstrably present in the nineteenth century and arguably in even earlier networks using visual signals. In September 1940 George Stibitz used a teletype machine to send instructions for a problem set from his Model at Dartmouth College in New Hampshire to his Complex Number Calculator in New York and received results back by the same means. Linking output systems like teletypes to computers was an interest at the Avanced Research Projects Agency(ARPA) when, in 1962, J.C.R. Licklider was hired and developed a working group he called the "Intergalactic Network"Bold text, a precursor to the ARPANet. In 1964, researchers at Dartmouth developed the Dartmouth Time Sharing System for distributed users of large computer systems. The same year, at MIT, a research group supported by General Electric and Bell labs used a computer DEC's to route and manage telephone connections. Throughout the 1960s Leonard Kleinrock, Paul Baran and Donald Davies independently conceptualized and developed network systems which used datagrams or packets that could be used in a network between computer systems.1965 Thomas Merrill and Lawrence G. Roberts created the first wide area network (WAN). The first widely used PSTN switch that used true computer control was the Weatern Electric introduced in 1965. In 1969 the University of Califirnia at Los Angeles, SRI in Stanford, University of California at Santa Barbara, and the University of Utah were connected as the beginning of the ARPANET network using 50 kbit/s circuits. Commercial services using X.25 were deployed in 1972, and later used as an underlying infrastructure for expanding TCP or IP networks. Computer networks, and the technologies needed to connect and communicate through and between them, continue to drive computer hardware, software, and peripherals industries. This expansion is mirrored by growth in the numbers and types of users of networks from the researcher to the home user. Today, computer networks are the core of modern communication. All modern aspects of the Public Switched Telephone Network (PSTN) are computer-controlled, and telephony increasingly runs over the Internet Protocol, although not necessarily the public Internet. The scope of communication has increased significantly in the past decade, and this boom in communications would not have been possible without the progressively advancing computer network.

BENEFITS
The benefits networking offers to its users can be separated into two main groups i.e. sharing and connectivity. Networks make computers and their users capable of being connected together. This facilitates sharing of resources and information between the users.The many benefits that networking offers to us are:


 * Help to enhance connectivity


 * Networks connect and link unlimited number of computers. This in turn connects the people using those computers. Individuals within a work group are connected through local area networks. Many LANs in far off locations are interconnected through larger wide area networks (WANs). These connections ease out communication between people using technologies like e-mail.


 * Networking helps in sharing of hardware
 * Networks help in sharing of different kinds of hardware devices. For example, sharing of a single printer in an office of twenty people is done through networking of wires.


 * Internet


 * The most beautiful gift of networking is internet that is massively used by people all over the world. Whenever you are accessing Internet, you are making use of a network. The benefits of internet need no mentioning.


 * Data sharing
 * Sharing of data through the use of networks helps save a lot of time and energy. It also facilitates the use of applications like databases that are based on ability of many individuals to access and to share exactly the same data.

WHAT IS NETWORK CLASSIFICATION
TWO TYPES OF NETWORKS BASED ON PHYSICAL SCOPE

The two types of network based oh their physical scopes are LOCAL AREA NETWORK (LAN) and WIDE AREA NETWORK (WAN).

LOCAL AREA NETWORK

A Local Area Network (LAN) is a network that connects computers and devices in a limited geographical area such as home, school, computer laboratory, office building, or closely positioned group of buildings. Each computer or device on the network is a node. Current wired LANs are most likely to be based on Ethernet technology, although new standards also provide a way to create a wired LAN using existing home wires such as coaxial cables, phone lines and power lines. All interconnected devices must understand the network layer such as layer 3, because they are handling multiple subnets which are the different colors. Those inside the library, which have only 10/100 Megabit/s Ethernet connections to the user device and a Gigabit Ethernet connection to the central router, could be called "layer 3 switches" because they only have Ethernet interfaces and must understand IP. It would be more correct to call them access routers, where the router at the top is a distribution router that connects to the Internet and academic networks' customer access routers. The defining characteristics of LANs, in contrast to WANs (Wide Area Networks), include their higher data transfer rates, smaller geographic range, and no need for leased telecommunication lines. Current Ethernet or other LAN technologies operate at speeds up to 10 Gbit/s. This is the data transfer rate.

WIDE AREA NETWORK

A Wide Area network (WAN) is a computer network that covers a large geographic area such as a city, country, or spans even intercontinental distances, using a communications channel that combines many types of media such as telephone lines, cables, and air waves. A WAN often uses transmission facilities provided by common carriers, such as telephone companies. WAN technologies generally function at the lower three layers of the OSI referrence Model which are :


 * physical layer


 * data link layer


 * network layer

BASIC HARDWARE COMPONENT

 * Power Supply - The power supply comes with the case, but this component is mentioned separately since there are various types of power supplies. The one you should get depends on the requirements of your system.


 * Motherboard - This is where the core components of your computer reside which are listed below. Also the support cards for video, sound, networking and more are mounted into this board.


 * Microprocessor - This is the brain of your computer. It performs commands and instructions and controls the operation of the computer.


 * Memory - The RAM in your system is mounted on the motherboard. This is memory that must be powered on to retain its contents.


 * Drive controllers - The drive controllers control the interface of your system to your hard drives. The controllers let your hard drives work by controlling their operation. On most systems, they are included on the motherboard, however you may add additional controllers for faster or other types of drives.


 * Hard disk drive(s) - This is where your files are permanently stored on your computer. Also, normally, your operating system is installed here.


 * CD-ROM drive(s) - This is normally a read only drive where files are permanently stored. There are now read/write CD-ROM drives that use special software to allow users to read from and write to these drives.


 * Floppy drive(s) - A floppy is a small disk storage device that today typically has about 1.4 Megabytes of memory capacity.


 * Monitor - This device which operates like a TV set lets the user see how the computer is responding to their commands.


 * Keyboard - This is where the user enters text commands into the computer.


 * Mouse - A point and click interface for entering commands which works well in graphical environments.

CONCLUSION
Computer communication, it seems, will become a much more useful networking tool when large numbers of people with similar interests acquire access to the technology. Though it can expedite the formation of new interpersonal networks by overcoming the space and time barriers faced by traditional networking techniques, it still requires a great deal of concentrated effort and resources to get the people to use it. This problem should become increasingly minimized over the coming years as the technological innovations become more diffused throughout society.

REFERENCE

 * http://benefitof.net/benefits-of-computer-network/
 * http://www.comptechdoc.org/hardware/pc/begin/hwcomputer.html
 * http://en.wikipedia.org/wiki/Computer_network