User:A131141 & A132564

Introduction
'''A computer network is a system in which computer are connected to share information and resources. The connection can be done as peer-to-peer or client/server. This web site reviews the techniques you can use to set up and possibly manage a network for home or a small business. It is also two or more computers connected so that they can communicate with each other and share information, software, peripheral devices, and/or processing power.'''

Background
'''In September 1940 George Stibitz used a teletype machine to send instructions for a problem set from his Model at Dartmouth Collegein New Hampshire to his Complex Number Calculator in New York and received results back by the same means. Advanced Researched Project 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 or distributed users of large computer systems.

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 Western Electric introduced in 1965.

'''The field of computer networking and today's Internet trace their beginnings back to early 1960s, a time at which the telephone network was the world's dominant communication network. The global Internet's origin was the Advanced Researched Projects Agency Network (ARPANET) of the U.S. Department of Defense in 1969s.'''

'''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
Connectivity and Communication

'''Networks connect computers and the users of those computers. Individuals within a building or work group can be connected into'''

'local area networks (LANs); LANs in distant locations can be interconnected into larger wide 'area networks (WANs)''. Once'''

'''connected, it is possible for network users to communicate with each other using technologies such as electronic mail. This'''

makes the transmission of business (or non-business) information easier, more efficient and less expensive than it would be

without the network.

Data Sharing

'''One of the most important uses of networking is to allow the sharing of data. Before networking was common, an accounting'''

employee who wanted to prepare a report for her manager would have to produce it on his PC, put it on a floppy disk, and then

'''walk it over to the manager, who would transfer the data to her PC's hard disk. (This sort of “shoe-based network” was sometimes'''

sarcastically called a “sneakernet”.)

'''True networking allows thousands of employees to share data much more easily and quickly than this. More so, it makes'''

possible applications that rely on the ability of many people to access and share the same data, such as databases, group

'''software development, and much more. Intranets and extranets can be used to distribute corporate information between sites and'''

to business partners.

Hardware Sharing

'''Networks facilitate the sharing of hardware devices. For example, instead of giving each of 10 employees in a department an'''

expensive color printer (or resorting to the “sneakernet” again), one printer can be placed on the network for everyone to share.

Internet Access

'''The Internet is itself an enormous network, so whenever you access the Internet, you are using a network. The significance of the'''

Internet on modern society is hard to exaggerate, especially for those of us in technical fields.

Internet Access Sharing

'''Small computer networks allow multiple users to share a single Internet connection. Special hardware devices allow the bandwidth'''

of the connection to be easily allocated to various individuals as they need it, and permit an organization to purchase one high-

speed connection instead of many slower ones.

Data Security and Management

'''In a business environment, a network allows the administrators to much better manage the company's critical data. Instead of'''

having this data spread over dozens or even hundreds of small computers in a haphazard fashion as their users create it, data can

'''be centralized on shared servers. This makes it easy for everyone to find the data, makes it possible for the administrators to'''

ensure that the data is regularly backed up, and also allows for the implementation of security measures to control who can read

or change various pieces of critical information.

Performance Enhancement and Balancing

Under some circumstances, a network can be used to enhance the overall performance of some applications by distributing the

computation tasks to various computers on the network.

Entertainment

'''Networks facilitate many types of games and entertainment. The Internet itself offers many sources of entertainment, of course. In'''

'''addition, many multi-player games exist that operate over a local area network. Many home networks are set up for this reason,'''

and gaming across wide area networks (including the Internet) has also become quite popular.

By Connection method
Computer networks can be classified according to the hardware and software technology that is used to interconnect the individual devices in the network, such as optical fiber,Ethernet, wireless LAN, HomePNA, power line communication or G.hn.

By range
Networks are often classified depending on their scale, scope and purpose. For example:
 * personal area network (PAN)
 * wireless PAN
 * local area network (LAN)
 * wireless LAN
 * metropolitan area network (MAN)
 * wide area network (WAN)

By functional relationship
Computer networks may be classified according to the functional relationships which exist among the elements of the network, examples are
 * client-server
 * multitier architecture
 * Peer-to-peer

By network topology
Computer networks may be classified according to the network topology upon which the network is based, such as bus network, star network, ring network, mesh network, tree and hypertree networks

By specialized function

 * Storage area networks
 * Server farms
 * Process control networks
 * Value added network
 * SOHO network


 * Wireless community network

TWO TYPES OF NETWORKS BASED ON PHYSICAL SCOPE
Wide Area Network (WAN)

A network of computer in a large geographic area for sharing resources or exchanging data.The internet connects multiple WANs; as its name suggests, it is a network of networks. In a WAN, one network may be anywhere from several hundred miles away, to across the globe in a different country. The first known of wide area network is in 1982. A wide area network that consists of the client and server computers that are distributed throughout the WAN, the functionalities of the network are distributed throughout the WAN. The internet is an example of the wide area network and is the most popular wide area network in this wolrd. The wide area network has made it possible for companies to communicate internally in ways never before possible. As a bonus, consumers can enjoy a number of benefits that vendors were not able to extend in the past.

WAN technologies and protocols are mostly data link layer (layer 2) protocols which are defined by many organizations over time. The key organizations in this space are IETF for PPP, ITU-T for ATM, Frame Relay, ISO for X.25 and SONET etc.

WAN technologies generally function at the lower three layers of the OSI reference model: the physical layer, the data link layer, and the network layer.

The main purpose of the WAN is to establish a secure, fast and reliable communicate channel among the people who are widely away from each other. Wide area networks are often privately owned networks. A wide area network uses many types of network devices such as WAN switches, access servers, CSU/DSU, modems, ISDN terminal adapters, routers, multiplexers, ATM switches and other networking devices. An example of the WAN is SURFnet, which is a research network and that connects the universities and research centers of the Netherlands with each other.

Local Area Network (LAN)

A local area network, also referred to as a LAN, is the local connection of computers to a network that share resources. Most LANs are confined to a single building or group of buildings. Typically, connected devices share the resources of a single processor or server within a small geographic area (for example, within an office building). Usually, the server has applications and data storage that are shared in common by multiple computer users. A local area network may serve as few as two or three users (for example, in a home network) or as many as thousands of users (for example, in an FDDI network).

Basic Hardware Components of Network
CPU (Central Processing Unit): CPU or central processing unit relates to a specific or processor. The performance of the computer is determined by the CPU chip (processor speed) and the other computer circuitry. Currently, the Pentium chip (processor) is the most popular even though there are other chips available in the market today such as AMD, Motorola and others. The clocks speed becomes most important factor in determining the performance of a computer. The motherboard contains the hardware circuitry and connections that allow the different hardware components of the PC to interact and communicate with each other. Most computer software is being developed for the latest processors so it would be difficult to use the older systems.

Hard Disk Drives – Disk drive is the mechanism to run the disks. All disks need a drive to get the information, read it and put it back to the disks. Hard disk is used to store the data permanently. Often the terms disk and drive used to describe the same thing but it should be clear that a disk is a storage device.

Modem – A modem is used for the modulation and demodulation of the data that is transferred through the modem and the telephone lines. Modem translates the data from digital to analog from analog to digital. Because on the telephone lines data can travel in the form of the analog signals and in the computer data transmits in the form of digital signals. Modems are measured by the speed which is called baud rate. The typical baud rate is 56Kb.

Keyboard – The keyboard is used to type something or input information to the computer. There are different designs and models of the keyboards in the market. The most common layout of the keyboard is QWERTY layout. A standard keyboard has 101 keys and embedded keys.

Video cards-Video cards allow computer to display video, graphics and animation. Some video cards allow computers to display television. A video card with a digital video camera allows users to produce live video. A high speed broadband internet connection is required to watch the videos on net.

Network cards: Network interface cards allow PCs to connect with each other and communicate. Every network computer is required to have a NIC card. NIC cards are required both in wired and wireless networking.

Cables: There are two broad types of cables internal cables, which are embedded on the mother board circuit that performs the communication between the devices and CPU. The other types of the cables are the network cables like coaxial cable, CAT 5, Ethernet cables. These cables are used for the communication purposes between the devices or computers.

Memory – Memory is the one of the important piece of the hardware. Sometimes memory chip memory is confused with the hard disk memory. Sometimes unallocated space of the hard disk is used as virtual memory also known as page file. This type of memory is a temporary memory and is used actual memory is less and requires some additional memory to perform a specific task.

RAM (Random Access Memory) - a memory that is being used by the computer to store the information temporarily. For example when some work is performed on some applications that work is temporarily stored in the RAM. More RAM in the computer more faster computer works. Today at least requirement of a modern PC is 64 RAM. RAM is in the form of a chip and different vendors have developed the RAM of different capacities.

Mouse – Every modern computer requires a mouse for faster operations. Generally a mouse has two buttons left and right to perform different functions. One type of the mouse has a round ball under the bottom. Another type of the mouse use optical system to track the movement of the mouse.

Monitors – The monitor is used to display the information on the screen. All the activities of a computer, functions and tasks are seen on the computer screen and this is called outputting information. Monitors come in many sizes and shapes, monochrome or full colors. Today most computers use LCD screens. It is light weight and consumes less power as compared to the monitors.

Printers – The printer takes the information from the PC and transfers it to the paper of different sizes, which are placed in the printer device. There are three basic types of a printer such as dot matrix, inkjet and laser.

Scanners- Scanners allow you to transfer pictures and photographs to your computer. A scanner is used to scan the images and pictures. You can then send the image to someone, modify it or take a print out of it. With optical character recognition software you can convert printed documents into the text that you can use in the word processor. Digital camera- You can take the digital photographs with the digital cameras. The images are stored on the memory chip of the digital cameras and you can transfer them to your computer with the USB drive.

Case – Case or casing covers the whole computer’s circuitry. There are two types of casings desktop and tower casing. There is room inside the casing to add or remove components. Cases come in many sizes like desktop, mini, midi and tower. There are some additional empty slots inside the cases such as IDE, USB, ASI, PCI and firewire slots.

Cards – Cards are the hardware components that are added to the computer to increase their functionalities and capabilities.

Sound cards produce the sound like music and voice. The older cars were 8, 16 and then 32 bits. Color cards allow computers to produce colors. Initially there were 2, 4 and then 16 bits. The main types of the graphic cards are EGA, VGA and SGA. The 32 cards are the standard to display almost billions of the colors on the monitor.

CONCLUSION
Networked computing has evolved from networks connecting computers and distributed computing through thin-client network computing in the 1980s and 1990s to Internet computing today. Centralized computing--which started with mainframes at the outset of the computing evolution, evolved to PCs, and lasted up to the 1980s--focused mainly on automating existing processes. This approach gave way as applications and systems evolved to the client-server model and the distributed computing model. The client-server model allowed for the creation of server applications responsible for the storage, analysis, and sorting of large amounts of data on central data servers, with connected workstations responsible only for front-end client applications capable of running queries, producing reports, and adding new records. Distributed computing meant that dedicated file servers also could be used throughout an internal Local-Area Network (LAN), each supporting a single application, such as e-mail, facsimile, data storage, graphics storage, or documentation storage. Computers, sometimes using different operating systems, could store different components of a single application, such as a spellchecker and thesaurus stored on different computers. Printers and other peripherals connected to the LAN offered users shared access over the network. Network monitoring and backups offered a high degree of data security and integrity. Personal computing entered a new era of productivity as spreadsheets, database programs, and word processors came increasingly into use at personal workstations.

Futurists predict that PCs will soon be replaced by network computers, Internet appliances (from telephone-like devices to televisions), and non-desktop computers, such as enterprise servers and wearable computers. As business transactions increasingly take place online, issues such as security, authentication, and quality of service (QoS) are expected to be resolved. Constant wireless connectivity and virtual private networks will allow users to be connected anytime, anywhere to their corporate nets over the Internet. As wireless communications expands, the convergence of video, voice, and data will allow users to download books, movies, television, and radio signals to their portables over broadband wireless connections. Computers will not only be everywhere, they will be held centrally on a network and controlled remotely. You could go to work, connect to your home server and control devices such as security cameras, motion detectors, lights, alarm clocks, heating and cooling systems, refrigerators, microwaves, PCs, televisions, and VCRs remotely.