Introduction to Network
:


The term ‘network’ in computing system means two or more computers connected with each other to form a network and term ‘networking’ means two or more computers connecting with each other and sharing data and resources.
Today, every sector in the world-banking, corporate offices, postal services,, schools and even homes where there are two or more computers, need a network to communicate with each other.
Computers were stand alone devices when first introduction. After a wide usage of computers, the manufacturers began to design hardware and software that would allow the computers to communicate with one another. Computer communication is described as a process in which one computer transfers the data, instructions and information to another computer.

Computer Network:


Computer networks make it easier for people to work with and manage their files by storing most information on a central computer. Users are often able to access their information from other computers on the network. The capability of providing access to and storage of data and information on shared storage devices is an important feature of many networks.

Sharing Resources:


Computer network is also used for sharing resources, such as printers and hard drives. Networks can help a company reduce the cost of buying computer hardware. For example, instead of buying a printer for each computer, connect the printer to all the computers in the network. In this way, all the network users can share one central printer.

Work from Home:


Many networks have computers that let people connect to the company’s network using a modem and a computer outside the network. Sitting at home, users can then work with network information.

Sharing Programs:


Many networks make installing programs very easy because only one copy of a program needs to be installed on a central computer. All network users can then access and work with an installed program.

Sharing Internet:


If a computer or other device has an internet connection, it can share that connection with other network users. This enables other users to access the internet without having to set up their own direct connection.

Productivity:


Networks can increase productivity by letting employees exchange information and communicate more easily. Through a network, people from different offices can work together on the same project.

Security:


Most networks have built-in security programs. These programs monitor and report any abnormal activity. Many security programs help to prevent unauthorized users from accessing information on the network.

Backup:


Many networks backup information on a central computer. When a backup is performed, only the information on central computer needs to be backed up.

Reliability:


Most networks are designed in such a way that they can provide uninterrupted service for a long time. Some networks can alert the network administrator if problems or errors occur.

Hardware requirements for networking:


All networks require special network hardware or components. Let’s see some hardware required for networking.

  • Computer:

Computer is the most important part because it is used to link together to form a network. When computers are linked, the network users can share information, views, documents, etc., easily.

  • Cables:

Cables are required to connect computers and resources on a network. Various kinds of cables can be used, depending on the type and size on the network. All cables used in electronics are insulated with a material such as plastic or rubber.

  • Communication Devices:

A communication device is any type of hardware capable of transmitting data, instructions, and information between sending devices and receiving devices. Communication devices could be of different types such as HUB, Switch, Modem, Route, etc. when two networks are connected, all the computers on both the networks can exchange information.

  • Resource:

Any part of a computer system or a network, such as a disk drive, printer, or memory, which can be allotted to a program or a process while it is running, is a resource.

  • Network Interface Card:

A network card sometimes called a network interface card (NIC, pronounced nick), is a communication device which enables a computer or a device that does not have built-in networking capability, to access a network. The network card coordinates the transmission and receipt of data, instructions, and information to and from the computer or device containing the network card.

Types of Network:


Networks are different types and sizes. Different types of networks are as follows:

  • Local Area Network (LAN):

A Local Area Network (LAN) is a group of networked computers that are relatively close together, such as in the same building. If you have a home network with two or more computers or you are connected to other computers at your school, then you are on a LAN. LANs are ideal for networking in a small geographical area and can either work with cables and hubs or wirelessly. They allow a speedy transfer of data up to 10Gbit/s. Most LANs are based on Ethernet technology. Wireless Local Area Network is also known as WLAN. A Wireless LAN (WLAN) is a LAN that uses no physical wires. Computers and devices that access a wireless LAN must have built-in wireless capability or the appropriate wireless network card.

  • Metropolitan Area Network (MAN):

A Metropolitan area network (MAN) is a high-speed network that connects local area networks in a metropolitan area such as a city or town and handles the bulk of communications activity across that region. A MAN typically includes one or more LANs, but covers a smaller geographic area that a WAN. The best known example of MAN is telephone companies, cable television operators, and other organizations available in many cities. Metropolitan Area Network is wider than Local Area Network.

  • Wide Area Network (WAN):

A Wide area network (WAN) is a network that is spread out over a relatively large geographical are, such as a city, country or even the world. The networks in a WAN are typically connected one large network or can consist of two or more LANs connected together. The internet is the world’s largest WAN.

Network Architectures:


The design of computers, devices and media in a network, sometimes called the network architecture, is categorized as either client/server or peer-to-peer.

  • Client/Server Network:

A client/server network is one where a large, powerful computer acts as a server and the other computers on the network request services from the server. A server sometimes called a host computer, controls access to the hardware, software and other resources on the network and provides a centralized storage area for programs, data, and information. The clients are other computers and mobile devices on the network that rely on the server for its resources. Clients connect to the server and use it to store files, run programs and implement security. For example a server might store a network version of an Ms-Excel program. Every client on the network can access the Ms-Excel program on the server. The client/server model is designed for large, complex networks. Window Server 2008, Mac OS X Server, and Novell NetWare are examples of client/server system.

  • Peer-to-Peer Networks:

In this network, computers can be directly connected to each and file and other information can be accessed directly by connecting to another computer. However, for this to take place, it is necessary that the computer from which the data need to be accessed should be turned ON. For example if computer 2 requires the X-file from Computer 1, it cannot do so if Computer 1 is turned OFF. Peer-to-Peer network is a simple, inexpensive network that typically connects fewer than 10 computers. Each computer, called a peer, has equal responsibilities and capabilities’, sharing hardware (such as a printer), data, or information with other computers on the Peer-to-Peer network.

Network topology:


In networking, the term topology refers to the layout structure of connected computers and devices on a network. Network typologies are categorized into the following basic types: A Bus Network consists of a single central cable, to which all computers and other devices connect. On a Start Network all of the computers and devices (nodes) on the network are connected to a central device, thus forming a start. On a Ring Network, a cable forms a closed loop (ring) with all computer all computers and devices arranged along the ring.



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